7. ---Could you tell me       the new library will be completed?

  ---In two years.

A. how long            B. how soon      C. how often         D. how far

6. ---Mum, is there any beef in the fridge?

  ---No, there is       left.

A. nothing      B. no one           C. none              D. nobody

5. If you are feeling sad, you’d better wear orange, because it can       you       .

A. wake …up      B. ring… up      C. pick…up           D. cheer…up

4. ---Why not       us in dancing?

  ---Good idea.

A. join             B. join in                C. take part in           D. attend

3. My brother is a       person. He feels sure about his own ability.

A. confident      B. selfish             C. patient          D. humorous

2. I am glad that I have learned at least 5 English songs       last month.

A. by               B. before                C. since                 D. until  

1. He is only       11-year-old boy, so he can’t do so much work in       hour.

A. an, a                          B. an, an                            C. a, an                             D. a, a

練習(xí)：甲乙兩人約好在9:00----10:00在某處會(huì)面。(1)求甲比乙早到的概率；(2)兩人約好，早到的人等另一人10分鐘后即可離去，求兩人會(huì)面的概率；(3)甲準(zhǔn)備到乙家，計(jì)劃在9:00---9:40任意時(shí)間內(nèi)到達(dá)，而乙在9:20---10:00等電話，接到電話后立刻離去，求兩人會(huì)面的概率。（(1);(2);(3)）

(2)AD在角BAC任意位置出現(xiàn)，概率為=

解：(1)D在BC任意位置出現(xiàn)，故概率為=