19.This is one of the equations ______ later when we want to calculate changes in speed.

　 A to use　　 　　　B to be used　　　 　C being used　　　 　　D having used

18.A glass rod will be electrified by ______ with a piece of silk.

　 A being robbed　　 B robbing　 　　　　C having robbed　 　　D having been robbed

17.The college students liked to watch the ships ______.

　 A being loaded and unloaded　　 B loading and unloading

　 C to be loaded and unloaded　　　 D to load and unload

16.I dislike ______ while attempting to learn skiing.

　A being looked at　　 B looking at　 　　　　C to look at　　 　　　D having looked at

15.The book is worthy of ______.

　 A reading　　 　　　　B read　　　 　　　　　C having read　　 　D being read

14.Having been asked to speak at convention, ______.

A.　　 some notes were prepared for Dr. Casagrande

B.　　　 Dr. Casagrande prepared some notes

C.　　　 The convention members were pleased to hear Dr. Casagrande

D.　　 Some notes were prepared by Dr. Casagrande

13.”How did the group improve its discussion?”

　 　“They all took part, each member ______ the responsibility of leading one meeting.”

　 A has　　 　　　　　B having　　　 　　　C has had　　 　　　D to have

12.He has come to ______.

　 A checked his blood pressure　　　　 B having his blood pressure checked

　 C have his blood pressure checked　　 D have checked his blood pressure

11.Do you remember ______ to professor Smith during your last visit?

　 A to be introduced　　 B being introduced　 C having introduced　 D to have introduced

10.While the ice box ______, a number of defects were found.

　 A was being examined　　 B was examined　　 C was examining　 D had been examined