1.The old lady didn't know ( ) when the house caught fire

.1.The old lady didn't know ( ) when the house caught fire
A.how to do B how to do it C.what to do D.what to do it
这题答案选C,B和C有什么区别呢?
语法上B也对,但是这里表示不知做什么,而非不知怎么做这件事.
2.I asked you ( ) he could come or not
Aif B.weather C.why D.whether
弱弱的问下：这题目答案是D,为什么不能选A?
whether可以和or not连用,而if 不可以.
3.A friend of ( ) came here yesterday
A.my B.his C.him D.himself
这道题想不通,为什么要选B- -为什么不是C
这是双重属格结构：a +名词+of+形容词性物主代词/名词所有格
所以这里his是名词性物主代词.如果把my改为mine也对.
这道题对初三来说有难度.加油!