CharlesSmith,______wasmyformerteacher,retiredlastyear.
A、whichB
that 不能引導非限制性定語從句 , 可以用 which 和 who 引導 , 其中 , who 代替的先行詞是人。句意為：查理 ?史密斯去年退休了 ,他曾經是我的老師。
If the operation ________ carefully prepared, it would not have been successful.
It rained hard yesterday, ______ prevented me from going to the park.
Heblamedhispoorperformance_____jetlag.
Wateriscomposed_______hydrogenandoxygen.
He blamed his poor performance_____jet lag.
