1.The real reason why prices ____________(be), and still are, too high is complex, and no short discussion can satisfactorily explain this problem.
2.(2021·通州期末)If we (keep) on doing this practice, gradually we'll learn how to express ourselves in English.
3.(2021·南通一模)—Kevin, time for the next destination!
—No hurry! Another 15 minutes and we _ _ (explore) all the exhibition rooms of the museum.
4.(2021·北京海淀区期中)—Mona is never happy.Look, she _ (complain) about her lunch.
—I think she'd better change her way of thinking.
5.(2021·陕西汉中一模)It was the first time that I _ (notice) the fresh taste of the meat and vegetables of Chinese food.