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
Children under six are not ______to school except those of extraordinary intelligence．
A．permitted B．admitted C accepted D．received
three times，but she still couldn’t follow what the old man said．
A．Having told B．Having been told
C．She had been told D．Though he had been told
一 Mom, guess what? I’ve won the 1st prize!
一 This a celebration! Let’s go to prepare a party．
A．helps out B．works out
C．calls for D．pays for
