Most scientists seem to agree that ____certain limit should be set on ______consumption of cars to ease air pollution.
| A．a；the | B．/；the | C．the；/ | D．the；the |
Between the two parts of the concert is an interval, ___ the audience can buy ice-cream.
| A．when |
| B．where |
| C．that |
| D．which |
___ from other continents for millions of years, Australia has many plants and animals not found in any other country in the world.
| A．Being separated |
| B．Having separated |
| C．Having been separated |
| D．To be separated |
When ___ help, one often says”Thank you” or”It is very kind of you”.
| A．offering |
| B．to offer |
| C．to be offered |
| D．offered |
The villager acting as our ___, we enjoyed our visit very much
| A．helper |
| B．assistant |
| C．leader |
| D．guide |
Only if you are ___ about your future, you can achieve your aim.So, don’t lose heart but cheer up.
| A．worried |
| B．curious |
| C．eager |
| D．optimistic |