15. Jerry did research in that field for a long time and ________invent something useful.

　　 A. got down to　　　　 　　　　　　　　　　　　　　　　 B. hoped himself to

　　 C. set out to　　　　　 　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　 D. devoted himself to

14. She told her husband that she couldn’t 　　　the rest of the housework without his help.

A．get over　　　　　　　　 B．get through　 　　　　　 C．get into　　　　　 D．get off

13. -Did you listen to the speech?

-No, we ________ it. But we had a lot of traffic on our way.

　　 A．must have attended　　 　　　　　　　　　　　　　　　　 B．must attend

　　 C．could have attended　 　　　　　　　　　　　　　　　　 D．should attend