快波睡眠的生物意义是（）。
A.促进生长和体力恢复
B.促进记忆和幼儿神经系统成熟
C.促进食欲和消化
D.促进脑电图同步化
参考答案：B
_______ the bad weather, the swimming match had been put off. [ ]
A. Because
B. Thanks to
C. With the help of
什么情况下程序会发生中断嵌套？
