Question

I ...............(not/see) Emma FOR/SINCE last week.
They.....(study) English FOR/SINCE three months.
Sarah.......(not/speak) to Eva FOR/ SINCE five days.
We. ......(be) there FOR/SINCE three hours.
He..........(look) for his keys FOR/ SINCE a long time.

Answer 1

1. I haven't seen Emma since..

2. The have studied English for..

3. hasn't speaking for...

4. have been for...

5. has looked for...

Правило: Present Perfect with Since and for

1. For - используется для чисел (for 3 days, for 2 month)

2. Since - используется для дат (since Thursday, since last year)