14.The students _____ four hours doing the reading assignmen

14.The students _____ four hours doing the reading assignments．
A．spent B．cost C．took D．finished
15.Tom is going to travel _____ the world on foot．
A．over B．across C．around D．through
16.I had rice and meat _____ lunch today．
A．in B．on C．for D．of
17.I should have gone to the opera yesterday．It was very good．I wish I ______ yesterday off．
A． have had B． had C．have D．had had
18.Do what you think is right _____ they say．
A．however B．whatever C．whichever D．for all
19.She is _____ something stupid．
A．so clever for doing B．too clever to do
C．very clever as to do D.clever enough to do
20.He wasn't ________ to lift the case．
A．too strong B．enough strong C．strong enough D．so strong
21.The train,_____ goes to Tianjin,is air-conditioned．
A． whom B．what C．which D．who