关于句子Sleep is part of a person's daily activity cycle.sleep可数还是不可数 有have a sleep的用法.但是没有人说some sleep……句子里为什么不是 a part of 还是因为 part of是个习惯用法?

关于句子Sleep is part of a person's daily activity cycle.sleep可数还是不可数 有have a sleep的用法.但是没有人说some sleep……句子里为什么不是 a part of 还是因为 part of是个习惯用法? Our Huangpu River is part of the Yangtze River这句句子是什么意思 Plenty of sleep is healthful急! 请问啊 Plenty of sleep is healthful 翻译文章：sleepSleep Sleep is part of a person’s daily activity cycle. There are several different stages of sleep, and they too occur in cycles. If you are an average sleeper, your sleep cycle is as follows. When you fist drift off into slumb Sleep is part of a person's daily activity cycle.There are several different stages of sleep,and they too occur in cycles.If you are an average sleeper,your sleep cycle is as follows.When you fist drift off into slumber,your eyes will roll about a bi what part of London is in France? What letter is a part of head? Discretion is the better part of What letter is a part of vegetable? the hardest part of skating is the what letter is part of the face? “What letter is a part of body? what part of the museum is this? Failure is a part of life短文 Which letter is a part of head Which letter is a part of body? Tibet IS a part of China