The examination will begin at 10:30. Those who come late ____ to the examination room.[ ]

A. have not been admitted

B. don't admit

C. will not be admitted

D. didn't admit

电能是现代入类使用最方便的能量．电能不但便于输送，而且转化为其他形式的能也很方便．电能的获得也很方便，可由各种形式的能转化而来．请将图补充完整．

①______；②______；③______；④______．