since、for

I am doing my homework ...... 4 A.M

• since

• for

We have collected 5 tons of rubbish ....... last month

• since

• for

I haven't seen him ............ 5 years

• since

• for

I have read 50 pages of this book .............. I started

• since

• for

I haven't completed this level .................. hours.

• since

• for

We have produced 50 milion tons of rubbish ............. last year

• since

• for

I I haven't gone to school .................. 1 year.

• since

• for

I have been here ............. twenty minutes.

• since

• for

He has worked in New York .................... a long time

• since

• for

He has worked in New York ................ he left school

• since

• for