They have know each other for 10 years.同意句 The have know each other ____2001.

问题描述:

They have know each other for 10 years.同意句 The have know each other ____2001.

填since.因为句子前面是现在完成时态,时间2001年一直延续到现在也有10年,所以填since意思就跟前面一句是一样的.