4C. Present Perfect Continuous

Kate Middleton is standing at the corner. She​ (a)   for the royal coach. She​ (b)   for the royal coach for twenty minutes.

• is waiting
• has been waiting
• was waiting
• has waited
• waits

Right now we're in class. We​ (a)   an exercise. We​ (b)   this exercise for a couple of minutes.

• are doing
• have been doing
• do
• have done
• were doing

A: You look busy right now. What ​ (a)   ?

B: I​ (b)   on my physics experiment. It's a long and difficult experiment.

A: How long​ (c)   on it?

B: I started planning it last January. I​ (d)   on it since then.

• are you doing
• am working
• have you been working
• have been working

A: I am tired. We _____ for more than an hour. Let's stop and rest for a while.

B: Okay.

• have walked

• were walking

• have been walking

• walked

A: Is the post office far from here?

B: Not at all. I _____ there many times.

• were walking

• have walked

• walked

• have been walking

A: Is Mr. Abdul your Fluid Mechanics' lecturer?

B: Yes, he is. He is one of the best lecturer here. He _____ Fluid Mechanics for more than 10 years.

• has taught

• was teaching

• taught

• has been teaching