One reason ______ Billy Crystal is popular with all age groups is _______ he is quick thinking and has the ability to amuse the audience.
| A．that, that | B．why, because |
| C．why, why | D．why, that |
Parent should take seriously their children’s requests for sunglasses _______ eye protection is necessary in sunny weather.
| A．unless | B．because | C．though | D．so |
--- Do you know the reason _________ pilots turn off the plane’s lights before taking off?
---The practice is for the passengers to adjust to the dark _________ an emergency.
| A．why; for fear that | B．for which; in case of |
| C．how; for fear of | D．that; in case |
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 |