Everyone of us has many responsibilities ______us．So we must work hard．
A．attaching B ．attaching to C．attatched with D．attatched to
The program was so fascinating that the children kept their eyes _____on the screen．
A．to fix B to be fixed C．fixed D．fixing
We must be sure that children in our country should get well ______．
A．educate B educating C．education D．educated
The professor devoted all his life ____the treatment of AIDS．
A to research B．in researching C．to researching D．at researching
----Where did you put the broom,Tom?
-----I _______it behind the door．But now it is gone．
A．do put B．do putting C．did to put D．did put
They experimented _____the new medicine _____animals．
A．on; to B by ; on C．with ; on D with; to
