A great explosion _______ in a chemical factory in Hangzhou several months ago.
| A．occurred | B．occurred to | C．has happened | D．has taken place |
_______ is announced in today’s newspaper, we have launched another man-made satellite.
| A．That | B．Which | C．As | D．What |
No sooner ______ the room than we realized we to take our books.
| A．had we left ; forget | B．we had left ; forget |
| C．we had left ; forgot | D．had we left; forgot |
When you’re learning to play the piano, _______ a good teacher makes a big difference.
| A．have | B．having | C．and have | D．if have |
—Is the manager available tomorrow afternoon? —No, he is busy. Otherwise he ________ the meeting.
| A．had attended | B．would have attended |
| C．would attend | D．could have attended |
— Mum, where is my ball? I remember I put it here yesterday. — You _______ it in the wrong place.
| A．must put | B．might put |
| C．might have put | D．should have put |