When did you go to Beijing?这句话用it is.that句型该怎么改,顺便说一下为什么这样改.

问题描述:

When did you go to Beijing?
这句话用it is.that句型该怎么改,顺便说一下为什么这样改.

被强调部分应为完整句子成分

强调句
when was it that u went to beijing?