先写成强调句：
It was yesterday that he helped the old man in the street.
在此基础上改成一般疑问句：
Was it yesterday that he helped the old man in the street?
特殊：
Wh...
把一个句子改成强调句型中的一般疑问句，特殊疑问句，和否定句
先写成强调句：
It was yesterday that he helped the old man in the street.
在此基础上改成一般疑问句：
Was it yesterday that he helped the old man in the street?
特殊：
Wh...