since和for后面的时态

表示过去已经开始持续到现在的动作或状态常用的时间状语有for, since, how long, so far, these days等。

for和since的用法区别

Since +时间点，具体时间。

“自从、、、、以来，从、、、以后” 用来说明动作起始时间

I have been in Beijing since 2010.

For + 时间段，用来说明动作延续时间长度，因此句中的谓语动词，也应该是延续性动词。

I have been in Beijing for one year。

We have learnt English for about three years.

I have been here for 3 days. (对)

I have arrived here for 3 days.（误）