分类：教育/科学-外语学习-英语考试
问题：过去进行时不明白的地方用when把两个句子合并成一句。Hecam 
用when把两个句子合并成一句。
He came downstairs.I had breakfast.
答案是：He came downstairs when i was having breakfast.
那么，能不能说：He　was  coming downstairs 
when i was having breakfast.
有什么区别？
请教各位，多谢！

回答：用when把两个句子合并成一句。 
He came downstairs.I had breakfast. 
答案是：He came downstairs when i was having breakfast. 
那么，能不能说：He　was coming downstairs 
when i was having breakfast. 
----不能这样说，因为英国人，美国人没有这样说的。主句和从句就是一个一般过去时，一个过去进行时。你说的本身就是一个病句。