Question 20. Peter _________ come with us tonight, but he isn't quite sure' yet.                           

A. can

B. may

C. will

D. must

Question 21. Huong really regrets _________ out of high school, She has really had to struggle to make her living because of that decision.                                          

A. dropping

B. drop

C. to drop

D. to have dropped

Question 22. At 5 o’clock yesterday evening, my elder sister _________ her clothes .                  

A. ironed

B. is ironing

C. has ironed

D. was ironing