单项选择题
A.he likes his job B.he works non-stop C.he is very punctual D.he repairs clocks and watches
A.robots never complain about the tiring work B.the management can pay little and benefit a lot C.it is dangerous for humans to do some harmful work D.they have their own weaknesses and advantages
A.Dark-colored clothes are warmer in the sunlight. B.Objects absorb part of the sunlight. C.Color is caused by reflected light rays. D.A red object reflects mostly red light.