（2011·河北正定中学第一次月考）17．The professor devoted all his life ____the treatment of AIDS．
A to research B．in researching C．to researching D．at researching
C考查短语devote to的用法。此处to为介词，其后用动名词。
（2011·河北正定中学第一次月考）15．They experimented _____the new medicine _____animals．
A．on; to B by ; on C．with ; on D with; to
C考查介词的用法。句意：他们用机器在动物身上做实验。
