第一节单项选择（共15小题；每小题1分，满分15分）
请认真阅读下面各题，从题中所给的A、B、C、D、四个选项中，选出最佳选项，并在答题卡上将该项涂黑。
例: It is generally considered unwise to give a child ________ he or she wants.
A. however B. whatever C. whichever D. whenever
-_____ you read the story?
-Yes. I _____ it at school.
| A．Have; read | B．Did; read |
| C．Have; have read | D．Did; have read |
There is only one more day to go ____ your favorite music group play live.
| A．since | B．until | C．when | D．before |
-Must I turn off the gas after cooking?
- Of course. You can never be ______ careful with that.
| A．enough | B．too | C．so | D．very |
Mr. Green stood up in defence of the 16-year-old boy, saying that he was not the one ______ .
| A．blamed | B．blaming | C．to blame | D．to be blamed |
Of the two sisters, Betty is _____ one, and she is also the one who loves to be quiet.
| A．a younger | B．a youngest | C．the younger | D．the youngest |