Zhang Luo, president of Beijing Tongren Hospital, checks a patient. People being sampled often s____or retch(呕吐).
Fan Zefeng, the village's Party chief, makes a _______at night.
Summer camp participants take part in scientific research, conservation work
Xie Xixian, 13, carefully picked sand off his slippers before placing it in a plastic bag and writing a l______to record where the sample was taken from.