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

练习：甲乙两人约好在9:00----10:00在某处会面。(1)求甲比乙早到的概率；(2)两人约好，早到的人等另一人10分钟后即可离去，求两人会面的概率；(3)甲准备到乙家，计划在9:00---9:40任意时间内到达，而乙在9:20---10:00等电话，接到电话后立刻离去，求两人会面的概率。（(1);(2);(3)）

(2)AD在角BAC任意位置出现，概率为=

解：(1)D在BC任意位置出现，故概率为=