_____ on May Day, the Shanghai Expo has attracted tens of thousands of visitors around the world every day．
| A．Having opened | B．Opened |
| C．Opening | D．To open |
Ournew machines are much cheaper to run．
| A．effective | B．efficient |
| C．energetic | D．Enthusiastic |
______ today, he would get there by Friday．
| A．Were he to leave | B．If he had left |
| C．Did he to leave | D．Had he left |
—Do you mind if I use your reference book?
—No, ______.
| A．look out | B．forget it |
| C．be my guest | D．take it easy |
I really don’t know______ Mary found her lost necklace that day.
| A．where was it that | B．where it was that |
| C．that where | D．it was that where |
The program “Master’s Lectures” of CCTV is both interesting and instructive. No wonder it_______ a large audience.
| A．accounts for | B．allows for |
| C．adapts to | D．appeals to |