第二部分 英语知识运用（共两节，满分45分）
第一节 单项填空（共15小题；每小题1分，满分15分）
从A、B、C、D四个选项中，选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑。
21. Obama, ________ president of the USA, won ________ Nobel Prize for Peace in 2009.
A. 不填；a B. 不填；the C. a；the D. the；a
"Life is like walking in the snow", Granny used to say, "because every step”
| A．has shown | B．is showing |
| C．shows | D．showed |
Sarah looked atfinished painting withsatisfaction.
| A．不填；a | B．a; the | C．the; 不填 | D．the; a |
---Which one of these do you want?
--- . Either will do .
| A．I don't mind | B．I'm sure |
| C．No problem | D．Go ahead |
After completing and signing it, please return the form to us in the envelope ________.
| A．providing | B．provided |
| C．having provided | D．provide |
The manager was concerned to hear that two of his trusted workers ______.
| A．will leave | B．are leaving |
| C．have left | D．were leaving |