精读三作业41.He suddenly saw a waterfall.It was an impressive sig

精读三作业4
1.He suddenly saw a waterfall.It was an impressive sight:the water seemed ____ straight out of the clouds.
a.to drop b.dropped c.to be dropping d.to have dropped
2.He intended ____ an accurate calculation last week.
a.to make b.to be made c.to have been made d.to have made
3.I am sorry to ____ the book for such a long time.
a.keep b.had kept c.have kept d.having kept
4.They appear ____ in the accident.
a.was injured b.to have been injured c.to injure d.being injured
5.She seemed ____ about it already.
a.hear b.hearing c.to hear d.to have heard
6.You seen ____ your health.
a.to recover b.to be recovering c.have recovered d.recovered
7.The next thing ____ is to oil the machine.
a.to be done b.to be doing c.do d.will be done
8.The old man is said ____ a very poor man when he was young.
a.to be b.he was c.to have been d having been
9.The gas seems ____ very quickly.
a.having expanded b.to have been expanding
c.to have expanded d.to expand
10.The research was known ____ for over 20 years.
a.to be going on b.to have been going on c.to have gone on d.to go on
11.They were glad ____ something for the people.
a.to have done b.to have doing c.to be done d.to have been done
12.He asked ____ re-elected since he had been chairman for seven years.
a.not to have been b.not to be c.to be not d.to have not been
13.The satellite is always escaping from the earth ____ back by gravity the same distance it has escaped.
a.to pull b.to have been pulled c.only to be pulled d.only being pulled
14.Much research in this field remains ____.
a.to do b.doing c.to be done d.to have been done
15.In order ____ into space,a great force is needed to overcome the force of gravity.
a.a satellite to launch b.for a satellite to be launched
c.for satellite to be launching d.to a satellite is launched
16.The child pretended ____ what his patents were saying.
a.to be not listening to b.to be listening not to
c.to not be listening to d.not to be listening to
17.The first aeroplane is said ____ of pieces of wood and cloth.
a.to have been made b.to have made c.to be made d.to make
18.Every device ____ in the spacecraft must be designed and made with great care.
a.to fit b.to fitting c.to be fitted d.fitting
19.I meant ____ you about it,but I forgot to do so.
a.telling b.to tell c.to have told d.to have telled
20.That factory is said ____ three times as many radios as it did last year.
a.to producing b.to be producing
c.to be produced d.to have been produced