I _________ here earlier, but I couldn’t catch the first bus.
| A．should come | B．have come | C．should be | D．should have come |
Mr. Smith, ______ in the factory for thirty years, is on the way back to his village.
| A．to work | B．working |
| C．to have worked | D．having worked |
—How was that?
—I was chatting on line _____ the power went out.
| A．because | B．while | C．as | D．when |
Our teacher always speaks slowly and clearly in class _____.
| A．so as to be understood | B．to have understood |
| C．so as to understand | D．to understand |
—Are you satisfied with the answer?
—Not at all. It couldn't have been ______.
| A．worse | B．so bad |
| C．better | D．the worst |
By the time Mr Wang returned home from Beijing, his son's wedding _______.
| A．ended | B．has ended |
| C．had been ending | D．had ended |