没有这种用法.
since+从句,主句.表已知必然理由,原因状语从句
since you have been here,you may stay here as well.
主句.(完成时态)since+从句(过去式).时间状语从句
it has been 3 years since I left home.
没有这种用法.
since+从句,主句.表已知必然理由,原因状语从句
since you have been here,you may stay here as well.
主句.(完成时态)since+从句(过去式).时间状语从句
it has been 3 years since I left home.