He after finishing his homework, so he soon.
A:feel sleepy; fall asleep
B:feel asleep; felt sleepy
C:felt sleepy; fell asleep
小明用150N的力竖直向上提起一个重100N的行李箱,则行李箱受到的合力大小是( )
将一张长方形纸片按照图示的方式进行折叠:
①翻折纸片,使A与DC边的中点M重合,折痕为EF;
②翻折纸片,使C落在ME上,点C的对应点为H,折痕为MG;
③翻折纸片,使B落在ME上,点B的对应点恰与H重合,折痕为GE.
根据上述过程,长方形纸片的长宽之比ABBC=____ .