目前我国预防艾滋病的基本措施之一是A．教育公众，洁身自爱，自我防护 B．查出所有艾滋

Jack and Mike were born on the same day and they look the same. The two children study in the same class. Jack works very hard on his study, but his brother Mike doesn’t like studying. He is not good at any of his lessons. He just likes playing computer games.

One day, their teacher asks them to write a composition(作文) about “Mother” at the weekend. On Sunday night, Jack writes his and after that, he helps his mother do some housework. But Mike goes out to play tennis for a long time. After he sees his bag, he thinks of his homework. But he doesn’t know how to write it. He thinks hard and then he has a good idea.

He goes into his brother’s bedroom and then finds Jack’s bag. He begins to copy the composition and then goes to bed happily. Two days later, his teacher asks Mike, “Can you tell me why your composition is the same as Jack’s?”

“Of course, we have the same mother.”

根据短文内容，选择正确答案（10分）

小题1:Why do Jack and Mike look the same?

A、Because they live near each other.

B、Because they are twins.

C、Because they are in the same class.

小题2:Who is good at school work?

A、Jack.                      B、Mike.            C、Jack and Mike.

小题3:What does Mike do when Jack writes his composition?

A、Helps his mother do some housework.

B、Writes his composition.

C、Plays tennis.

小题4:What does the underlined word “copy” mean in Chinese?

A、复制                   B、抄袭            C、复印

小题5:Why does the teacher come to talk with Mike?

A、Because Mike’s composition is the same as Jack’s.

B、Because Mike writes a good composition.

C、Because Mike doesn’t write his composition.

李老师买篮球和排球各a个，篮球每个56元，排球每个42元．李老师一共用了（______）元，买排球比买篮球少用了（______）元．

分别说明生态系统的组成部分。

等比数列a_n的前n项和为S_n，且4a₁，2a₂，a₃成等差数列。若a₁=1，则S₄=（）。

A．7

B．8

C．15

D．16

E．以上答案均不正确

压井管汇的压力级别和组合形式应与（）压力级别和组合形式相匹配.

A.放喷管线；

B.防喷器；

C.液气分离器；

D.钻井泵。