A.when different flowers open and close |
B.if flowers have a mysterious way of knowing the time |
C.how flowers are used to tell the time in the darkness |
D.why flowers open and close at particular time |
A.would never open in darkness |
B.would change their usual time to open |
C.would continue to open at their usual time |
D.would open earlier than the usual time |
A.sunlight |
B.weak light |
C.the “inner clock” |
D.the information from the outside world |
A.wild animals | B.human beings |
C.all creatures(生物) | D.lifeless things |
A.we will have more strength to do our work. |
B.clocks or watches are no longer useful to us |
C.we will be able to live as long as we wish to |
D.human beings will need less sleep, less food or less movement |