单项选择题

Questions 19 to 22 are based on the conversation you have just heard. 您的浏览器不支持 audio 元素。

A. They have difficulty identifying these cells.
B. They aren’t sure how these cells work.
C. They’ve learned how to reproduce these cells.
D. They’ve found similar cells in other species.
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单项选择题
A. He thinks she should visit her cousin. B. Her cousin doesn’t visit very often. C. Her cousin is feeling a lot better today. D. He doesn’t think her cousin has been at home today.
A. He thinks she should visit her cousin.
B. Her cousin doesn’t visit very often.
C. Her cousin is feeling a lot better today.
D. He doesn’t think her cousin has been at home today.
单项选择题
A. Sleeping pills made people go into REM sleep quickly.B. People had more dreams after they took sleeping pills.C. People became angry easily because they didn’t take sleeping pills.D. Sleeping pills prevented people from going into REM sleep.
A. Sleeping pills made people go into REM sleep quickly.
B. People had more dreams after they took sleeping pills.
C. People became angry easily because they didn’t take sleeping pills.
D. Sleeping pills prevented people from going into REM sleep.
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