when的用法We were about to leave when he came in.这句句子中when作并列连词

副词 ad.
1.(用作疑问副词)什么时候,何时
I'd like to know when they'll let him out.
我想知道他们什么时候放他.
When did you last see Margaret?
你上一次见到玛格丽特是什么时候?
2.(用作关系副词,引导关系从句)当...时
There were times when I didn't know what to do.
有些时候我不知道该怎么办才好.
连接词 conj.
1.当...时
John got engaged to her when travelling last winter.
去年冬天旅行时,约翰与她订了婚.
Don't get excited when you talk.
你说话时别激动.
2.既然,考虑到
How can he get the promotion when his boss dislikes him?
既然上司不喜欢他,那他怎么会获得提升呢?
3.虽然,然而
I had only fifteen dollars on me when the book I wanted cost twenty.
我身上只带了十五元钱,可是我想买的那本书定价二十元.
4.在那时,然后
代词 pron.
1.什么时候,那时
Since when has she taught here?
她从什么时候开始在这儿教书的?
名词 n.
1.(事件发生的)时间[the S]