Many a student _______ that mistake before.

问题描述:

Many a student _______ that mistake before.
是had made 还是has made?before不是过去时的标志吗?had made过去完成时放在句子中不行吗?

应该是 has made
分析 before 以前,常与现在完成时连用.
加油!不明白再问!所以before是现在完成时的时态标志吗?是的, 还有already , yet ,just 等I had fallen asleep before you came back。这个是过去完成时啊注意,这句中的before 是介词‘ 在……之前’因为动词发生在CAME 之前,所以主句要用过去完成时。