题文
The flu is believed __________ by viruses that like to reproduce in the cells inside the human nose and throat.
| A.to be caused |
| B.to have caused |
| C.being caused |
| D.causing |
推荐试卷
The flu is believed __________ by viruses that like to reproduce in the cells inside the human nose and throat.
| A.to be caused |
| B.to have caused |
| C.being caused |
| D.causing |
试题篮
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