We can never expect____ bluer sky unless we create_____less polluted world.
| A．a; a | B．a; the |
| C．the; a | D．the; the |
The process of curing a disease is like a war ___ different soldiers fight against an enemy.
| A．when | B．where | C．what | D．that |
In a sports team each player has a clear role，and there are few occasions members are confused or uncertain of their roles．
| A．which | B．that | C．when | D．how |
That so-called football fan doesn’t even know the main difference between the two football teams, _____ surprises all of the people at present.
| A．which | B．what | C．that | D．where |
Carol said the work would be done by October, _________ personally I doubt very much.
| A．that | B．when | C．it | D．which |
In the dark street，there wasn’t a single person she could turn for help．
| A．that | B．who | C．to whom | D．from whom |