We walked along the beach for nearly three hours _______ we saw a boat on the sea.
问题描述：
We walked along the beach for nearly three hours _______ we saw a boat on the sea.
为什么只能用before而不能用until.
答
用until意思说不通啊.用BEFORE整句意思是:在看见船之前,我们已经在海边走了将近3个小时.如果用until,翻译过来变成：我们在海边走了近三个小时,直到我们看到船.感觉“我们在海边走了近三个小时，直到我们看到船。”也可以，虽然用before更好。另外主句为什么不用完成时态？一般在before词形为副词作时间状语时，用现在完成时，例如：I have never seen such a kind man before.这里只是作介词，不用完成时。例：You must go to bed before 10 o'clock.