for vs since

I have been waiting _______ 4 o'clock.

• since
• for

Sue has only been waiting _______ 20 minutes.

• since
• for

Tim and Tina have been learning English _______ six years.

• since
• for

I ______________ (do) much work ___________ my boss left.

• didn't do  /  for
• haven't done  /  for
• didn't do  /  since
• haven't done  /  since

They have been learning French _______ 1998.

• since
• for

I left the university in 1995. I ___________ (work) in this company ____________ about fifteen years.

• have worked  /  since
• did work  /  for
• worked  /  since
• have worked  /  for

Joe and Josephine have been going out together _______ Valentine's Day.

• since
• for

I ______________ (be) to China ______________ 2002.

• didn't go  /  for
• haven't been  /  since
• haven't gone  /  for
• wasn't  /  since

I haven't been on vacation _______ last July.

• since
• for

Hi, Angela. How are you? I ____________ (not/see) you ___________ ages.

• haven't seen   /  for
• didn't see  /  since
• haven't seen  /  since
• didn't see  /  for