Evolve 3 Unit 2- Since or for?

I've known Janet _______________ a long time.

• for

• since

I've known her _______________December.

• for

• since

We haven't seen Andy _______________ three days.

• for

• since

He hasn't seen Jade _______________ Monday.

• for

• since

I've been living here _______________ a year.

• for

• since

We've been living here _______________ 2009.

• for

• since

Liz has studied English _______________ two years.

• for

• since

Jake and John have been classmates _______________ six months.

• for

• since

Mike and John have been classmates _______________ last summer.

• for

• since

We have not met them ____________eight years.

• for

• since