英语时态：When all those present were seated he began his lecture.
问题描述：
英语时态：When all those present were seated he began his lecture.
When all those present were seated he began his lecture.
观众入场以后他才开始演讲,那观众入场就是过去的过去,应该用过去完成时的被动语态猜对呀,为什么这里用的是一般过去时的被动语态?
答
Be seated,please.请坐.（很礼貌的用法）
seat sb.某人就座（有安排,使的意味 ）
seat 的特点是作动词时为及物动词,后面必须有宾语或用其被动语态
这里的When all those present were seated,只是一种观众就坐的状态
用When引导的时间状语从句
“那些到场的人全坐下时,他才开始演说”,
前半句是时间状语从句,且从句有被动意思.主从句时态保持一致,主句he began his lecture,为一般过去时态,所以从句也要用一般过去时态,1.all those present were seated我如何确定这是主系表结构还是被动语态呢 怎么理解都可以呀2.那就是说所有从句的时态都要跟主句一致？是这个意思吗？应该是主系表吧 be seated,其实表面上看是被动，什么“被引导入座”啊，其实不是的，它和sit的意思是一样的，都是“坐下”的意思，这里是系表结构，表示所有人都坐下的状态。 那就是说所有从句的时态都要跟主句一致？不对哦还要看里面有没有出现by, before等构成的短语，有可能是过去完成时具体还要看题意 观众坐下和开始演讲发生时间一致，所以用过去时