原子量是不是原子质量:He didn't know which hat was his. 还是应该用：He didn't know which hat his was.

He didn't know which hat was his. 还是应该用：He didn't know which hat his was. As he didn't know the lesson at_____,Tom failed his English test. 1English is very useful in m----- word.2He didn't say a w------ about it. Didn't you know? No,I didn't.答句应该怎么翻译 We didn't know ______such a difficult problem. The conductor didn't know w____ to do. I didn't know nothing的意思是什么? I didn't know the answer,__. A.so does heB.so did heC.nor did heD.neither he did(理由) He didn't buy anything yesterday 变为被动语态 he didn't dare to draw a deep breath