1. we were so disappoited that most of the guests _______ when we arrived at the party.
a. leave b. left c. have left d. had left
2. because his argument was so confusing __________ people understood it.
a. a few b. much c. few d. many
3. there are a lot of letters ________ right now.
a. to be written b. to have written c. to be writing d. to write