for和since的用法有什么不同都用于现在完成时,但具体怎么分
问题描述：
for和since的用法有什么不同
都用于现在完成时,但具体怎么分
答
for+时间点，since+时间段. + . +
答
for后面是跟一段时间，而since的用法主要有两点：一是表示“自从……以来”，二是表示“既然”之意。since后跟某个固定时间或日期。
答
for加段时间 since加时间点 。。。。。。。。这是最明白的答法了！
答
since+某一时间点或句子,for+一段时间
I have been here for over 10 years.
I have been here since 10 years ago
答
很简单.
since+时间点/ 句子,for+时间段
1 I have been here for about 10 years.
2 I have been here since 10 years ago
3 I have been here since I was 10 years old.
4 I have been here since 2001