Read the sentences and choose since or for.

1. It has been raining ..... this morning.
for
since

2. I've been working on the project ..... January.
since
for

3. We've been here ..... nine o'clock.
for
since

4. She hasn't had a day off ..... 1999.
for
since

5. I've worked here ..... April.
since
for

6. We've been waiting for you ..... twenty minutes.
since
for