Only after you explained it to me ____ it was not my teacher’s fault.
| A．I realized | B．had I realized | C．realized I | D．did I realize |
By the time he realizes he ____into a trap, it’ll be too late for him to do anything about it.
| A．walks | B．walked | C．has walked | D．had walked |
The wet weather will continue tomorrow when a cold front ______ to arrive.
| A．is expected | B．is expecting | C．expects | D．will be expected |
—Have you known Dr. Jackson for a long time?
—Yes, since she________ the Chinese Society.
| A．has joined | B．joins | C．had joined | D．joined |
—Have you got any job offers?
—No. I ______.
| A．waited | B．had been waiting | C．have waited | D．am waiting |
--- I’m sure Andrew will win the first prize in the final.
--- I think so. He ___________ for it for months
| A．is preparing | B．was preparing |
| C．had been preparing | D．has been preparing |