- 试题详情及答案解析
- Some new oilfields ________ since 1976.
| A．were opened up | B．will be opened up |
| C．have opened up | D．have been opened up |
- 答案：D
- 试题分析：句意：自从1976年，一些新的油田被开放了。A. were opened up 一般过去时的被动 B. will be opened up一般将来时的被动C. have opened up 现在完成时D. have been opened up现在完成时的被动。since 是现在完成时的标志词，油田和开放是被动关系，故选D。
考点：考查动词时态的用法。