During the past two decades, research has ________ our knowledge of daydreaming.
A
A扩大B浮现、露出C下降D征服
People who can ’t _______ between colors are said to be color -blind.
Neverbefore_______sorapidlydevelopingasitistoday．
The farming methods have been ________ improved with the invention of the new machine.
Robots differ from automatic machines ________ after completion of one specific task，they can be reprogrammed by a computer to do another one.