【高考突破方案】强化训练 选择性必修第三册 Unit 5 Learning from nature 高考一轮总复习英语（外研版）（含答案）

强化训练
Ⅰ.阅读理解
A
(2025·清远市一模)
Muscle contraction hardening is necessary for enhancing strength and it also enables rapid reactions in living organisms. Taking inspiration from nature, a team of researchers from Queen Mary University of London (QMUL) has successfully created an electronic artificial muscle that changes between soft and hard states while also possessing the remarkable ability to sense forces and deformations.
Dr Ketao Zhang, a lecturer at QMUL and the lead researcher, explains the importance of variable hardness technology in artificial muscle like actuators (执行器) . “Empowering robots, especially those made from flexible materials, with self sensing capabilities is a key step towards true bionic (仿生) intelligence，” says Dr Zhang.
The advanced artificial muscle developed by the researchers exhibits flexibility and stretchability similar to natural muscle, making it perfect for integration into complicated soft robotic systems and adapting to different shapes. With the ability to bear over 200% stretch along the length direction, this flexible actuator shows exceptional durability.
By applying different voltages (电压), the artificial muscle can rapidly adjust its hardness, achieving continuous hardness changes over 30 times. Its voltage driven nature provides a significant advantage in terms of response speed over other types of artificial muscles. Additionally, this wonderful technology can monitor its deformation through resistance changes, removing the need for additional sensor arrangements and simplifying control mechanisms while reducing costs.
This flexible variable hardness technology can be widely used, ranging from soft robotics to medical applications. The integration with the human body opens up possibilities for aiding individuals with disabilities or patients in performing necessary daily tasks. By integrating the self sensing artificial muscle, wearable robotic devices can monitor a patient's activities and provide resistance by adjusting hardness levels, facilitating muscle function restoration.
“While there are still challenges to be addressed before these medical robots can be employed in clinical settings, this research represents an important step towards human machine integration，” highlights Dr Zhang. “It provides a blueprint for the future development of soft and wearable robots.”
语篇导读：本文为一篇说明文。文章主要介绍了一个研究小组从大自然中汲取灵感，成功创造了一种电子人造肌肉，这种肌肉可以在软硬状态之间变化，同时还具有感知力和变形的非凡能力。
1．What is a feature of the muscle developed by the researchers from QMUL
A．It responds slowly in speed.
B．It is able to stretch flexibly.
C．It functions without electricity.
D．It is equipped with extra sensors.
解析：B　细节理解题。根据第三段“The advanced artificial muscle developed by the researchers exhibits flexibility and stretchability similar to natural muscle, making it perfect for integration into complicated soft robotic systems and adapting to different shapes. With the ability to bear over 200% stretch along the length direction, this flexible actuator shows exceptional durability.(研究人员开发的先进人造肌肉展示了与天然肌肉相似的柔韧性和伸展性，使其非常适合集成到复杂的软机器人系统中，并适应不同的形状。这种柔性执行器能够承受超过200%的长度方向拉伸，显示出卓越的耐用性。)”可知，QMUL研究人员开发的肌肉的特点是它能灵活地伸展。故选B。
2．What does paragraph 5 mainly tell us about variable hardness technology
A.Its working principles.
B．Its design inspirations.
C．Its potential applications.
D．Its future improvements.
解析：C　主旨大意题。根据第五段“This flexible variable hardness technology can be widely used, ranging from soft robotics to medical applications. The integration with the human body opens up possibilities for aiding individuals with disabilities or patients in performing necessary daily tasks. By integrating the self sensing artificial muscle, wearable robotic devices can monitor a patient's activities and provide resistance by adjusting hardness levels, facilitating muscle function restoration.(这种灵活的硬度可变技术可以广泛应用于从软机器人到医学应用。与人体的结合为帮助残疾人或病人完成必要的日常任务开辟了可能性。通过集成自感应人造肌肉，可穿戴机器人设备可以监控病人的活动，并通过调整硬度水平提供阻力，促进肌肉功能恢复。)”可知，第五段主要告诉我们关于可变硬度技术的潜在应用，可以帮助病人和残疾人的日常活动，可以监控病人的活动。故选C。
3．What can we infer about the research from Dr Zhang
A．It is of great significance.
B．It lacks experts' responses.
C．It hardly meets challenges.
D．It has been applied to hospitals.
解析：A　推理判断题。根据最后一段“‘While there are still challenges to be addressed before these medical robots can be employed in clinical settings, this research represents an important step towards human machine integration，’ highlights Dr Zhang.‘It provides a blueprint for the future development of soft and wearable robots.’(张博士强调：‘尽管这些医疗机器人应用于临床环境之前仍有一些挑战需要解决，但这项研究代表了人机集成的重要一步。它为软的可穿戴的机器人的未来发展提供了蓝图。’)”可推知，张博士的研究意义重大，代表了人机集成的重要一步。故选A。
4．Which of the following is the best title for the text
A.A Promising Device—an Artificial Muscle like
Actuator
B.A Science Blueprint—the Future Development of
Robots
C．An Unsolved Challenge—Perfect Human Machine
Integration
D．A Bionic Breakthrough—Self Sensing Electric
Artificial Muscles
解析：D　主旨大意题。根据文章第一段“Muscle contraction hardening is necessary for enhancing strength and it also enables rapid reactions in living organisms. Taking inspiration from nature, a team of researchers from Queen Mary University of London (QMUL) has successfully created an electronic artificial muscle that changes between soft and hard states while also possessing the remarkable ability to sense forces and deformations.(肌肉收缩硬化对于增强力量是必要的，它还能使生物体迅速反应。受自然的启发，来自QMUL的研究团队成功创造了一种电子人造肌肉，这种肌肉可以在软硬状态之间变化，同时还具有感知力和变形的非凡能力。)”可知，文章主要介绍了研究人员创造了电子人造肌肉，这种肌肉可以在软硬状态之间变化，同时还具有感知力和变形的非凡能力，可以应用到医学领域，是一种新的突破，故D项“仿生突破——自感应电子人造肌肉”符合文章标题。故选D。
B
(2025·河南洛阳市高三监测)
The next big development in cancer treatment could be a vaccine(疫苗). After years of limited success of vaccines to treat camera, scientists say research has made many advancement.
Many doctors predict more vaccines will be out in five years. They are not traditional vaccines that prevent diseases. Instead, they are shots to shrink tumors(肿瘤) and stop the cancer from coming back. Targets for these experimental treatments include breast, 1 mg melanoma(黑素瘤), etc.
More than ever, scientists understand how cancer hides from the body's immune system(免疫系统). Cancer vaccines, like other immune system treatments, strengthen the immune system to find and kill cancer cells. Some new cancer vaccines use mRNA, which was developed for cancer. For a vaccine to work, it needs to teach the immune system's T cells to recognize cancer to be dangerous. Once trained, T cells can travel anywhere in the body to hunt down danger.
Drug producers Moderna is developing an mRNA vaccine tailored for patients with pared with other melanoma vaccines，Moderna's vaccines are designed for each patient, based on the many differences in their cancer tissue, which can train the immune system to hunt for the cancer cells and kill them.
The vaccines under development at the University of Washington are designed to work for many patients. Tests are ongoing in early and advanced breast and lung cancer. Some results may come as soon as next year. Jamie Crase was one of the first people to receive the lung cancer vaccine. Crase was diagnosed with advanced lung cancer at age 34. She thought she would die young. Now she is 50, with no sign of cancer. She does not know for sure if the vaccine helped. But she said, “I'm still here.”
语篇导读：本文是一篇说明文。文章主要介绍了癌症治疗的下一个重大发展可能是疫苗，并且研究已经取得了一些进展。
5．What can future cancer vaccines do according to many doctors
A.Get rid of tumors.
B．Increase immune cells.
C．Avoid cancer reappearance.
D．Prevent cancers in advance.
解析：C　细节理解题。根据文章第二段“Many doctors predict more vaccines will be out in five years. They are not traditional vaccines that prevent diseases. Instead, they are shots to shrink tumors(肿瘤) and stop the cancer from coming back.(许多医生预测，未来五年内会有更多的疫苗问世。它们不是预防疾病的传统疫苗。相反，它们被注射来缩小肿瘤并阻止癌症复发。)”可知，未来的癌症疫苗能避免癌症复发。故选C。
6．What is Paragraph 3 mainly about
A．The danger cancer cells bring.
B．The way cancer vaccines work.
C.The function of the immune system.
D．The composition of cancer vaccines.
解析：B　主旨大意题。根据文章第三段“For a vaccine to work, it needs to teach the immune system's T cells to recognize cancer to be dangerous. Once trained, T cells can travel anywhere in the body to hunt down danger.(为了使疫苗起作用，它需要教会免疫系统的T细胞识别癌症是危险的。一旦被训练，T细胞可以在身体的任何地方寻找危险。)”可知，本段主要介绍了癌症疫苗是如何起作用的。故选B。
7．How special is Moderna's vaccine
A．It uses mRNA.
B．It is personalized.
C．It can hunt down danger.
D．It focuses on cancer tissue.
解析：B　细节理解题。根据文章倒数第二段“Moderna's vaccines are designed for each patient, based on the many differences in their cancer tissue, which can train the immune system to hunt for the cancer cells and kill them.(Moderna的疫苗是根据每个患者癌症组织的许多差异设计的，可以训练免疫系统寻找癌细胞并杀死它们。)”可知，Moderna的疫苗的特别之处在于它是个性化的。故选B。
8．What can be predicted according to the last paragraph
A．Cancer is no longer a threat.
B．The vaccines have gone through tests.
C．More patients will benefit from the vaccines.
D．Progress on cancer treatment has been slow.
解析：C　推理判断题。根据文章最后一段“Jamie Crase was one of the first people to receive the lung cancer vaccine. Crase was diagnosed with advanced lung cancer at age 34. She thought she would die young. Now she is 50, with no sign of cancer. (杰米·克莱斯是第一批接种肺癌疫苗的人之一。Crase在34岁时被诊断出患有晚期肺癌。她以为自己会英年早逝。现在她50岁了，没有癌症的迹象。)”可推知，疫苗让患有肺癌的杰米·克莱斯受益，因此推断未来会有更多的病人将受益于疫苗。故选C。
Ⅱ.完形填空
(2025·汕尾市四校联考)
One summer night in a seaside cottage, a boy felt himself 1. from bed. Then he was held in his father's arms out onto the nearby beach. Overhead the sky twinkled with stars. “Watch！” 2. ， as his father spoke, one of the stars moved. In a line of golden fire it flashed across the dark3. . And before the wonder of this could 4. ， another star leaped from its place, then another, diving towards the restless sea.
“What's this？” the child whispered.
“Shooting stars. They come every year on a certain August night. I thought you'd like to see the 5. ．”
That was all: just an unexpected 6. of something mysterious and beautiful. But back7. ， the child stared for a long time into the dark, knowing that all around the quiet house the night was full of the 8. music of the falling stars.
Decades have passed, but he still remembers that night because he was the 9. boy whose father believed that a new experience was more important for a small boy than a(n) 10. night's sleep. No doubt he had all the usual childhood entertainment, but those are 11. now. What he remembers is the night of the shooting stars, and the “trophy(战利品)table” in the dining room where children were encouraged to 12. things they had found— anything 13. or beautiful—snake skins, seashells, flowers, arrowheads...
His father had, to a marvelous degree, the gift of opening doors for children, of leading them into areas of splendid 14. . This subtle(巧妙的) art of 15. dimensions to a child's world doesn't necessarily require a great deal of time. It simply involves doing things more often with children instead of for them or to them.
语篇导读：本文为一篇记叙文，讲述了一个小男孩被父亲从睡梦中抱出去看美丽的流星而久久不能忘怀的故事，这位父亲鼓励男孩去探索和体验新的事物，带领他进入新的领域。
1．A.called　　　　　 B．lifted
C．knocked D．transported
解析：B　句意：一个夏天的晚上，在海边的小屋里，一个男孩觉得自己被从床上抱了起来。A.called喊，叫；B.lifted举起，抬起；C.knocked撞击，碰击；D.transported运输。根据下文“Then he was held in his father's arms out onto the nearby beach.”可知，小男孩被父亲从床上抱了起来，用lift表示“抱起”。故选B。
2．A.Incredibly B．Anxiously
C．Simply D．Curiously
解析：A　句意：令人难以置信的是，就在他父亲说话的时候，一颗星星动了。A.Incredibly不可思议地；B.Anxiously焦急地；C.Simply仅仅；D.Curiously好奇地。根据下文“one of the stars moved”可知，一颗星星移动了，这是不可思议的，令人难以置信的。故选A。
3．A.sea B．face
C．eyes D．heavens
解析：D　句意：金色的火焰在黑暗的天空中闪烁。A.sea大海；B.face脸；C.eyes脸；D.heavens天空。根据上文“Overhead the sky twinkled with stars.”及“it flashed across the dark”可知，黑色的是天空，流星在天空中划过。故选D。
4．A.fade B．work
C．attack D．continue
解析：A　句意：在它的奇迹还没有消失之前，另一颗星星从它的位置跳了出来，然后又一颗，向那不安的海洋俯冲而去。A.fade消失；B.work工作；C.attack攻击；D.continue继续。根据“before”及“another star leaped from its place, then another, diving towards the restless sea”可知，在第一颗流星的奇迹还没有消失之前，第二颗又出现了。故选A。
5．A.weather B．place
C．show D．condition
解析：C　句意：我认为你会想看这个景色。A.weather天气；B.place地方；C.show景象；D.condition条件。根据前文“Shooting stars”及上文父亲将孩子抱出来看流星可知，父亲认为孩子会想要看这个景象。故选C。
6．A.comeback B．blow
C．glimpse D．visit
解析：C　句意：仅此而已：只是意外地瞥见了神秘而美丽的东西。A.comeback再度流行；B.blow刮风，打击；C.glimpse一瞥，短暂的感受；D.visit参观。根据上文“In a line of golden fire it flashed across the dark 3 . And before the wonder of this could 4 ， another star leaped from its place, then another, diving towards the restless sea.”可知，流星划过时，只是对神秘而美丽的东西的一瞥，只是短暂的感受。故选C。
7．A.to the beach B．under the sky
C．in bed D．to his seat
解析：C　句意：但是回到床上，孩子盯着黑暗看了很长时间，他知道寂静的房子周围充满了流星的无声的音乐。A.to the beach去海滩；B.under the sky天空下；C.in bed床上；D.to his seat回到座位上。根据“But back”可知，之前孩子被父亲从床上抱出来，现在指又回到了床上。故选C。
8．A.serious B．silent
C．modern D．sad
解析：B　句意：同上。A.serious严肃的；B.silent寂静的；C.modern现代的；D.sad伤心的。根据“music of the falling stars”可知，流星划落是没有声音的。故选B。
9．A.cautious B．ambitious
C．fortunate D．sensitive
解析：C　句意：几十年过去了，但他仍然记得那个晚上，因为他是一个幸运的男孩，他的父亲认为，对一个小男孩来说，新的经历比一夜安稳的睡眠更重要。A.cautious谨慎的；B.ambitious有抱负的；C.fortunate幸运的；D.sensitive敏感的。根据“whose father believed that a new experience was more important for a small boy than a(n) 10 night's sleep.”可知，父亲更加重视体验新事物，探索新事物，男孩是幸运的。故选C。
10．A.restless B．heavy
C．light D．unbroken
解析：D　句意：同上。A.restless坐立不安的，没有休息的；B.heavy重的，超出一般的；C.light轻的，浅的；D.unbroken未破损的，不间断的。根据文章开头“One summer night in a seaside cottage, a boy felt himself 1 from bed.”可知，孩子的一晚上不间断的睡眠被父亲打破了，因此，此处表示比起不间断的睡眠，新的经历更重要。故选D。
11．A.resolved B．forgotten
C．avoided D．delayed
解析：B　句意：毫无疑问，他童年时有过所有的娱乐活动，但现在那些都被遗忘了。A.resolved决心；B.forgotten忘记；C.avoided避免；D.delayed延迟。根据“No doubt he had all the usual childhood entertainment, but”及下文“What he remembers is the night of the shooting stars”可知，童年有过的娱乐活动，男孩在长大后忘记了。故选B。
12．A.create B．search
C．collect D．exhibit
解析：D　句意：他记得的是那个流星的夜晚，还有餐厅里的“奖杯桌”，孩子们被鼓励展示他们发现的东西——任何不寻常的或美丽的东西——蛇皮、贝壳、花、箭头……A.create创造；B.search搜寻；C.collect收集；D.exhibit展示。根据“things they had found—anything 13 or beautiful—snake skins, seashells, flowers, arrowheads...”可知，孩子们被鼓励将发现的东西展示出来。故选D。
13．A.unusual B．uncertain
C．practical D．awful
解析：A　句意：同上。A.unusual不寻常的；B.uncertain不确定的；C.practical实际的；D.awful糟糕的。根据“or beautiful—snake skins, seashells, flowers, arrowheads”可知，列举的东西是不寻常的。故选A。
14．A.victory B．sky
C．newness D．cottage
解析：C　句意：他的父亲有着惊人的天赋，能够为孩子们打开大门，带领他们进入崭新的领域。A.victory 胜利；B.sky天空；C.newness新奇，崭新；D.cottage农舍。根据上文“because he was the 9 boy whose father believed that a new experience was more important for a small boy”可知，父亲更重视孩子们体验新事物，他有着为孩子们开启通往崭新领域大门的天赋。故选C。
15．A.adding B．applying
C．turning D．tracing
解析：A　句意：这种为孩子的世界增加维度的微妙艺术并不一定需要大量的时间。A.adding添加；B.applying申请，应用；C.turning转；D.tracing追踪。根据“It simply involves doing things more often with children instead of for them or to them.”可知，父亲带男孩看流星，带领孩子探索新的世界，这可以为孩子的世界增加维度，让孩子有更多的体验。故选A。
Ⅲ.七选五
(2025·浙江强基联盟联考)
How to Keep a Pet Bird Quiet
Birds can be excellent companions, but they can also make a lot of noise. Sometimes that noise is unavoidable, but there are a few steps you can take to train your bird out of loud or continuous squawking (尖叫).
1. Most birds tend to make some noise, either by singing or squawking. Birds tend to be most vocal during waking hours in the morning and before going to sleep in the evening. Some birds are more likely to make noise than others, but understand before bringing a bird home that some noise will be unavoidable.
Teach your bird to speak softly. Praise your bird when he whistles or whispers, instead of squawking or yelling. 2. It's often easier to teach them soft spoken words compared to other types of sounds. Furthermore, it's important to maintain a calm and gentle tone when interacting with your bird. 3. Because this could strengthen the behavior you are trying to discourage.
Avoid quick movements. It's possible that you or someone in your household is moving too quickly around your bird, causing him to feel anxious or over stimulated. 4. If you have children living at home, teach them not to run through the room your bird is in.
Provide your bird with comfort and security. Birds in the wild participate in “flock calls” as a way of communicating with other birds and ensuring the safety of the flock. If your bird is likely to squawk when you leave the room, it could be his attempt at sending you a flock call. 5.
A．Understand bird behavior.
B．Train your bird to be quiet.
C．This may be especially useful for parrots.
D．Give him a treat for quietness to earn your love.
E．Try squawking back to let him know that you're safe.
F．Do not raise your voice in response to your bird's volume or tone.
G.Move slowly around your bird, and encourage others to do the same.
语篇导读：本文是一篇说明文。短文介绍了如何让宠物鸟保持安静。
解析：
1．A　根据下文“Most birds tend to make some noise, either by singing or squawking. Birds tend to be most vocal during waking hours in the morning and before going to sleep in the evening.(大多数鸟都会发出一些声音，不是唱歌就是叫。鸟类在早上醒着的时候和晚上睡觉前往往是最大声的。)”可知，本段主要介绍要了解鸟儿的行为。故A选项“了解鸟的行为。”切题，为本段的标题。故选A。
2．C　根据上文“Praise your bird when he whistles or whispers, instead of squawking or yelling.(当你的鸟吹口哨或低语时，赞美它，而不是尖叫或吼叫。)”可知，选项承接上文说明其对哪种鸟类有作用。故C选项“这可能对鹦鹉特别有用。”切题。故选C。
3．F　根据上文“Furthermore, it's important to maintain a calm and gentle tone when interacting with your bird.(此外，当你和你的鸟交流时，保持冷静和温和的语气是很重要的。)”可知，选项承接上文具体说明保持冷静和温和的语气。故F选项“不要提高你的声音来回应你的鸟的音量或音调。”切题。故选F。
4．G　根据上文“Avoid quick movements. It's possible that you or someone in your household is moving too quickly around your bird, causing him to feel anxious or over stimulated.(避免快速移动。有可能是你或你家里的人在你的鸟周围移动得太快，导致他感到焦虑或过度刺激。)”可知，选项承接上文说明在鸟周围缓慢移动的重要性。故G选项“慢慢地在你的鸟周围移动，并鼓励其他人也这样做。”切题。故选G。
5．E　根据上文“Provide your bird with comfort and security. Birds in the wild participate in ‘flock calls’ as a way of communicating with other birds and ensuring the safety of the flock. If your bird is likely to squawk when you leave the room, it could be his attempt at sending you a flock call.(给你的鸟一个舒适和安全的环境。野外的鸟类参与‘鸟鸣’，作为与其他鸟类交流和确保鸟群安全的一种方式。如果你离开房间时，你的鸟可能会吱吱叫，这可能是它试图向你发出鸟鸣。)”可知，上文提到要采取一些措施来确保鸟感到安全和舒适。所以建议通过模仿鸟的叫声来回应， 是一种提供安全感的方式，因为它可能被鸟理解为一种群体间的交流，表明它并不孤单。故E选项“试着用叫声回应，让他知道你很安全。”切题。故选E。
Ⅳ.语法填空
(2025·河南洛阳市高三监测)
Baduanjin, a kind of exercise regarded as a unique sport among the aged, has gained 1. (popular) among the young people in China.
More than 1，000 videos about Baduanjin can be found on Bilibili, 2. video platform in China. A video 3. (release) by the General Administration of Sport of China to teach the public has gained about 10 million views and about 6，000 4. (comment). Most of them were from college students and the young people.
The exercise also becomes part of PE class at a college. “Our school asked us to do this exercise and sent a video 5. our PE teacher，” said an Internet user. Film stars and fitness bloggers also do this exercise, 6. has attracted a large number of followers.
7. (date) back to the Song Dynasty (420—479), Baduanjin has a history of more than 800 years. It 8. (consist) of eight movements, using limbs to stimulate meridians(经络)inside the body. Compared with Tai Chi, Baduanjin is 9. (suitable) for beginners with its simple and gentle movements. It can enhance immunity and enable people 10. (relax). It is also a very low cost social activity for the young people in China.
语篇导读：本文是一篇说明文。文章主要介绍了拥有悠长历史的健身运动——八段锦。
解析：
1．popularity　考查名词。句意：八段锦，一种被认为是老年人独特的运动方式，在中国的年轻人中很受欢迎。设空处在句中作宾语应用名词的形式，表示抽象概念，为不可数名词。故填popularity。
2．a　考查冠词。句意：在中国视频平台哔哩哔哩上可以找到1，000多个关于八段锦的视频。设空处后为名词单数，表示泛指，应用不定冠词，空后的形容词为辅音音素开头。故填a。
3．released　考查非谓语动词。句意：中国体育总局发布的一段教育公众的视频已经获得了大约1，000万的点击量和约6，000条评论。设空处在句中作非谓语，和其逻辑主语之间是逻辑的被动关系。应用动词过去分词的形式作定语。故填released。
4．comments　考查名词。句意：同上。设空处为名词在句中作宾语，空前为“about 6，000”可知，设空处应为名词复数的形式。故填comments。
5．to　考查介词。句意：一位网友说：我们学校要求我们做这项运动，并把视频发给了我们的体育老师。send sth. to sb.将某物(寄/发送给某人)。故填to。
6．which　考查定语从句的引导词。句意：电影明星和健身博主也在做这项运动，这吸引了大量的粉丝。设空处引导非限制性定语从句，且在句中作主语，主语为前面的整个句子，应用which。故填which。
7．Dating　考查非谓语动词。句意：八段锦的历史可以追溯到宋朝(420—479)，已有800多年的历史。设空处在句中为非谓语作状语，和句子的逻辑主语之间是逻辑的主动关系，应用现在分词的形式，位于句首，首字母应该大写。故填Dating。
8．consists　考查谓语动词。句意：它包括八个动作，用四肢刺激体内的经络。设空处在句中作谓语，叙述客观事实，应用一般现在时，主语为it，结合主谓一致。故填consists。
9．more suitable　考查形容词。句意：与太极拳相比，八段锦动作简单柔和，更适合初学者。设空处应为形容词在句中作表语，根据“Compared with Tai Chi(与太极拳相比)”可知，设空处应用形容词的比较级的形式。故填more suitable。
10．to relax　考查非谓语动词。句意：它可以增强免疫力，使人放松。设空处在句中作非谓语，“enable sb. to do sth.使某人能够做某事”，设空处应用动词不定式的形式。故填to relax。