单项选择题：由于成品冷凝器循环水中断而造成塔压升高时，应立即（）。A.把塔内物料排空 B.切断热

题型：阅读理解

阅读理解

Bob is an English boy. He is a good student. He is in a white coat. Amy is a girl. She is Bob's sister.

She is a very nice girl. She is in a green sweater.

Lucy and Lily are Americans. They are sisters. They like the same color. They are in red sweaters.

They are students, too.

Bob, Amy and the sisters are good friends. Bob and the sisters are in the same school, but Amy isn't

a student. She is only five years old. She is at home.

1. Bob is __________.

A. English

B. American

C. Chinese

D. Japanese

2. Amy is __________.

A. Lucy's sister

B. Lily's sister

C. Bob's sister

D. a student

3. What color is Amy's sweater?

A. It's red.

B. It's green.

C. It's white.

D. It's yellow.

4. Bob, Amy, Lucy and Lily are __________.

A. in the same school

B, good students

C. good friends

D. brothers and sisters

5. Which of the following is right?

A. Bob has two sisters.

B. Lucy and Lily like different colors.

C. Lucy is an English girl.

D. Bob. is Amy's brother.

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题型：解答题

化简求值：
（1）（5a²-3b）-3（a²-2b），其中a=2，b=-3
（2）（2x²-xy+7）-（-4x²+2xy+7），其中x=-

1

2

，y=2．

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题型：单项选择题

土壤中含氮化合物在氨化微生物的作用下，分解成氨和胺盐，这种现象是因为

A．环境的富集作用

B．环境的迁移作用

C．环境的自净作用

D．植物的光合作用

E．污染物的不稳定作用

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题型：单项选择题

正常心室功能曲线不出现降支的原因是（）

A.心肌的伸展性较小，静息张力较大

B.心肌的贮备能量较多

C.心肌的静息张力较小

D.心肌的伸展性较大

E.心肌收缩的潜在能力较大

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题型：单项选择题

若某航空公司的飞机订票系统有n个订票终端，系统为每个订票终端创建一个售票终端的进程。假设P_i(i=1，2，…，n)表示售票终端的进程，H_j(j=1，2，…，m)表示公共数据区，分别存放各个航班的现存票数，Temp为工作单元。系统初始化时将信号量S赋值为 (26) 。P_i进程的工作流程如图2-10所示，a、b和c处将执行P操作和V操作，则图2-10中a、b和c应填入 (27) 。

A．P(S)、V(S)和V(S)

B．P(S)、P(S)和V(S)

C．V(S)、P(S)和P(S)

D．V(S)、V(S)和P(S)

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由于成品冷凝器循环水中断而造成塔压升高时，应立即（）。A.把塔内物料排空 B.切断热

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