1. _________ a major role in future planetary exploration.
A．Robots will surely play
(B)Robots, which will surely play
(C)Because robots will surely be playing
D．Surely robots, which will be playing
2. Unlike the owl, bats cannot see very well, but they do have_________.
A．it hears very well
(B)very good to hear
(C)tearing very well
D．very good hearing
3.Comparatively few clues in the United Slates have competing newspapers today, a major change from 1900 _________ more than two newspapers.
A．because then most large cities having
(B)when did most large cities have
(C)then most large cities that had
D．when most large cities had
4.Witch hazel extract, _________ distilled from the bark and twigs of the witch hazel shrub, has been utilized in medicine.
A．is
B．when to be
(C)which is
D．has been
5. _________ touching in O. Henry’s stories is the gallantry with which ordinary people struggle to maintain their dignity.
A．Most is
B．It mostly is
C．Is it most
D．What is most
6. The face of the Moon is changed by collisions with meteoroids, _________ new craters to appear.
A．cause
B．causing
C．caused
D．have cause
7. Social scientists believe that _________ from sounds such as grunts and barks made by early ancestors of human beings.
A．the very slow development of language
B．language developed very slowly
C．language which,, was very slow to develop
D．language, very slowly developing
8. _________ substances include various forms of silica, pumice, and emery.
A．Natural abrasives occur
B．Abrasion occurs in natural
C．Naturally occurring abrasive
D．A natural occurrence of abrasion
9. _________ in the upper part of their long1 thin legs all9w deer to run swiftly and jump far.
A．Muscles are powerful
B．There are powerful muscles
C．The powerful muscles that
