单项选择题

Babies sleep 16 to 18 hours in every 24 hours, and they sleep less when they grow older.

A．对
B．错

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Translate the following terms into Chinese (the underlined terms in thetext).
tax breaks

答案： \n \n \n \n (1)\n ...

单项选择题

移液器使用中应该注意

A．吸液体的时候要快，快速移液才能防止滴漏
B．吸液体的时候要慢一些，避免液体快速通过吸头，喷入移液器内
C．吸液体时要快，避免液体挂壁