论文部分内容阅读
1. She used to be a history teacher.(Lesson 2)她过去曾是一名历史教师。used to中的to为不定式符号,后接动词原形,构成used to do sth句型,意为“过去曾经/常常做某事”,其否定式有两种:didn’t use to…和used not to…;其疑问式也有两种:Did…