We couldn’t understand: what could ______ his sudden change of mind?
| A．enjoy | B．explain | C．accept | D．mean |
—Do you know where David is? I couldn't find him anywhere.
—Well, he ______ have gone far—his coat's still here.
| A．shouldn't | B．mustn't | C．can't | D．wouldn't |
She is getting better, but it will be some time ______ she is completely well.
| A．that | B．since | C．when | D．Before |
The computer centre, ______ last year, is very popular among the students in this school.
| A．open | B．opening |
| C．having opened | D．Opened |
______ in thought, he almost ran into the car in front of him.
| A．Losing | B．Having lost |
| C．Lost | D．To lose |
—What did your parents think about your decision?
—They always let me do ______ I think I should.
| A．when | B．that | C．how | D．What |