单项选择题
A.so B.therefore C.since D.as
It's not safe（）in the street.A.playedB.playC.playingD.p...
单项选择题It's not safe（）in the street.
A.played B.play C.playing D.plays
He（）himself quickly to the new condition of his work.A....
单项选择题He（）himself quickly to the new condition of his work.
A.changed B.altered C.adjusted D.varied
I have spent a lot of time（）working on this problem.A.a...
单项选择题I have spent a lot of time（）working on this problem.
A.at B.–（不填） C.on D.with
