4.设两个独立事件A和B都不发生的概率为，A发生B不发生的概率与B发生A不发生的概率相同，则事件A发生的概率P(A)是　　　　 .

答案　

3.若X-B(5，0.1)，则P(X≤2)=　　　　 .

答案　 0.991 44

2.(2008·南师附中模拟)已知某一随机变量的概率分布如下，且E()=6.3，则a的值为　　 　　.

	4	a	9
P	0.5	0.1	b

答案　 7

1.设随机变量X的分布列由P(X=i)=C·确定，i=1，2，3，则C的值为　　　　 .

答案　

70. “He is a little noisy, but o_______ he is a good boy,” said the mother.

第五节： 短文改错 (每题1分，共10分)

　　 　David joined the army when he was eighteen. And for　

several months he taught how to be a good soldier.　　　　　 71_______

He did quite good in everything except shooting. One day he　 　72_______

and his friends are practising their shooting, and all of　　　　 73______

them did well besides David. At last the officer said, “David!　　 74_______

You are quite hopeless! Do not waste your bullets.　　　　　 75_______

Go behind the wall, and shoot you.” David felt ashamed. He　　 76_______

went behind the wall and a few seconds late the officer　　　　 77_______

and the others young soldiers heard a sound of a shot　　　　 78______

“Heavens!” the officer said, “has that silly man really shooted　 79______

himself?” He ran behind the wall anxious. But David was all　　 80______

right. “I am sorry, sir,” he said “But I missed again.

第六节　 书面表达(满分15分)

我国正提倡建设“节约型社会”，下图为某校两个学期用水、用电、用纸的情况。请对其进行简要分析，以 “How to build an economized society”为题，写一篇作文，谈谈自己的想法。

	用　 电	用　 水	用　 纸
上学期	80万元	62万元	11万元
下学期	95万元	73万元	12.7万元

文章须包括以下要点：

节电：及时关闭电灯、电脑等用电设备

节水：随手关闭水龙头；废水利用

节纸：纸张再利用

补充：自己日常生活所感所为

注意：

词数：100-120字，短文标题，开头已给出，但不计入总词数。

内容可适当发挥，注意行文贯通。

How to build an economized society

Our government is aiming to build an economized society. It is everybody’s duty to work hard to achieve this goal including us students.

69. The a________ temperature in summer here is about 22C.

68. Entering Grade Three, you should adjust some of your studying ________ ( 策略 ).

67. It is believed that these big stones were t_______ here with the help of the aliens.

66. The Opening C_______ of the 2008 Olympic Games was splendid.

65. Water can ____ (吸收)and give off a lot of heat without big changes in temperature.