At the beginning of this century, medical scientists made an interesting discovery: we are built not just of flesh(肌肉) and blood but also of time. They were 21 to show that we all have a ‘body clock’ 22 us, which controls the 23 and fall of our body energies, 24 us different from one day to the next. The 25 of a ‘body clock’ should not be too 26 since the lives of most living things are controlled 27 the 24-hour night-and-day cycle(循环). We feel 28 and fall asleep at night and become 29 and energetic during the day. If the 24-hour cycle is 30 most people experience unpleasant 31 . For example, people who are not 32 to working at night can find that 33 of sleep causes them to 34 badly at work. 35 the daily cycle of sleeping and 36 , we also have other cycles which 37 longer than one day. Most of us would 38 that we feel good on some days and not so good on 39 ; sometimes our ideas seem to flow and at other times, they 40 do not exist. 小题1: A．anxious B．careful C．able D．proud 小题2: A．around B．inside C．between D．on 小题3: A．rise B．supply C．use D．movement 小题4: A．showing B．treating C．changing D．making 小题5: A．idea B．opinion C．story D．invention 小题6: A．difficult B．exciting C．interesting D．surprising 小题7: A．from B．over C．by D．during 小题8: A．dull B．dreamy C．tired D．peaceful 小题9: A．regular B．excited C．clear D．lively 小题10: A．shortened B．disturbed C．reset D．troubled 小题11: A．moments B．senses C．feelings D．effects 小题12: A．used B．allowed C．expected D．prevented 小题13: A．miss B．none C．need D．lack 小题14: A．show B．perform C．manage D．control 小题15: A．With B．Except C．As well as D．Rather than 小题16: A．waking B．moving C．living D．working 小题17: A．repeat B．remain C．happen D．last 小题18: A．believe B．agree C．realize D．allow 小题19: A．others B．the other C．all other D．other 小题20: A．only B．just C．still D．yet