“ Although ,” the boy said , “ _______ over and over , the maths problem remained confusing to me ” .
| A．explained | B．explain |
| C．explaining | D．having explained |
I think you must be mistaken about seeing him at the theatre； I’m sure he ____abroad all week.
| A．is | B．was | C．has been | D．had been |
They haven’t arrived yet but we _____ them at any moment.
| A．are expected | B．have expected | C．are expecting | D．will expect |
I feel sure I _____ her before somewhere.
| A．was to meet | B．have met | C．had met | D．would meet |
You’ll never guess who I met today — my old teacher！ We _____ for 20 years.
| A．don’t meet | B．haven’t met | C．hadn’t met | D．couldn’t meet |
I _____ your last point — could you say it again？
| A．didn’t quite catch | B．don’t quite catch | C．hadn’t quite catch | D．can’t quite catch |