since 和 when在现在完成时中的区别
问题描述:
since 和 when在现在完成时中的区别
比如 I have been skating since I was7 years old 为何不能用when 什么时候用when
多举几个例句 然后分别说明主句从句接什么时态
别复制长帖子 3Q
答
since指从过去一时刻到现在:I have been skating since I was7 years old .
when强调时间点:I had finshed my homework when he go home.