At the beginning of this century, medical scientists made an interesting discovery; we are built not just of flesh and blood but also of time. They were   36   to show that we all have “a body clock”   37    us, which controls the   38   and fall of our body energies,   39   us different from one day one to the next. The   40   of “a body clock” should not be too   41   since the lives of most living things are controlled   42   the 24 hour night-and-day cycle. We feel   43   and fall asleep at night and become   44   and energetic during the day. If the 24 hour-cycle is   45   , most people experience unpleasant   46   . For example, people who are not   47   to working at night can find that   48   of sleep causes them to   49   badly at work. 50   the daily cycle of sleeping and   51  , we also have other cycles which   52   longer than one day. Most of us would   53   that we feel good on some days and not so good on    54   ; sometimes our ideas seem to flow and at other times, they   55   do not exist. 36．A．anxious                  B．able                        C．careful                    D．proud 37．A．inside                     B．around                    C．between                  D．on 38．A．movement                     B．supply                    C．use                         D．rise 39．A．showing                 B．treating                   C．making                   D．changing 40．A．invention                B．opinion                   C．story                      D．idea 41．A．difficult                  B．exciting                  C．surprising               D．interesting 42．A．from                      B．by                          C．over                       D．during 43．A．dull                       B．tired                             C．dreamy                  D．peaceful 44．A．regular                   B．excited                   C．lively                            D．clear 45．A．disturbed                B．shortened                C．reset                       D．troubled 46．A．moments                B．feelings                  C．senses                     D．effects 47．A．prevented               B．allowed                  C．expected                 D．used 48．A．miss                      B．none                       C．lack                        D．need 49．A．perform                  B．show                      C．manage                   D．control 50．A．With                      B．As well as               C．Except                    D．Rather than 51．A．working                 B．moving                   C．living                     D．waking 52．A．repeat                     B．remain                    C．last                         D．happen 53．A．agree                      B．believe                   C．realize                   D．allow 54．A．other                      B．the other                 C．all other                  D．others 55．A．just                        B．only                       C．still                        D．yet