---What is our earth like ________from the moon?
---Well, our earth, with water ________ 70% of its surface, appears as a "blue ball".
| A．seen; covering | B．seen; to cover |
| C．seeing; covered | D．seeing; covering |
33．— Can I help you?
— Do you have any of Michael Jackson's CDs ? I would like to buy _____．
| A．it | B．one | C．that | D．Those |
32．Tens of thousands of trees _____ in the area in the past few years．
| A．have been planted | B．were planted | C．have planted | D．had planted |
31．— I'm wondering why the visitors chose to stay with the host family．
— _____real local life．
| A．Experiencing | B．Experience | C．To experience | D．Having experienced |
30．How long do you think it will be _____ we can find a new water source?
| A．after | B．before | C．when | D．Since |
29．High up in the mountains _____ a quiet small village, with only 20 households．
| A．surrounds | B．locates | C．lies | D．Lays |