句型转换

因为“was/were doing”中的was/were是助动词，所以在进行句型转换中要注意不需要再另外借助助动词do/did/does，而是直接借用was/were。如：

肯定句：I was trying to work out a solution to the problem at this time yesterday.

否定句：I wasn't trying to work out a solution to the problem at this time yesterday.

一般疑问句：Were you trying to work out a solution to the problem at this time yesterday?

特殊疑问句：What were you trying to work out at this time yesterday. (划线部分为a solution to the problem)