流体在管中稳定流动时的流速与管内径的关系是（） A.与管内径成正比 B.与管内径的平

画一个直径2厘米的圆，用字母标明圆心、半径和直径．

补全对话 阅读对话，从每题ABCD四个选项中，选出一个最佳答案完成对话。

A: Hello.    66    

B: This is Mike speaking.

A: Hi, Mike. This is Jack. Are you going to the school party tomorrow?

B: Yes, I am.    67    

A: Me, too. And I will bring my cousin Dave with me. He arrived yesterday.

B:      68    

A: What will happen if I do?

B: If you bring Dave, the teacher will ask him to leave      69    

A: What a pity!

B: By the way,      70     If you don’t have your ID card, you can’t go to the party.

A: Thank you for reminding me. See you tomorrow.

B: See you.

小题1:

A．May I speak to Mike?

B．How are you?

C．What’s your name?

D．I want to talk to you.小题2:

A．What do you do?

B．What about you?

C．Are you OK?

D．How are you?小题3:

A．He is my best friend.

B．What’s your idea?

C．Maybe you can’t do that.

D．Can you come?小题4:

A．because he is friendly.

B．because you are welcomed.

C．because he is not a student.

D．because he isn’t studying in our school.小题5:

A．Don’t leave anything.

B．Don’t forget to take your ID card.

C．Remember to bring your cousin.

D．Please wear your jeans.

阅读材料并回答问题：

材料一  通常食醋中约含3%～5%的醋酸．醋酸的化学式为CH₃COOH，在温度高于16.6℃时是一种无色液体，易溶于水，醋酸具有酸的通性．

材料二  钙是人体中的一种常量元素，人们每日必须摄入一定量的钙．动物的骨头中含有磷酸钙，但磷酸钙难溶于水，却能跟酸反应生成可溶性的钙盐．

（1）在10℃时，醋酸的状态是 _________ ；

（2）生活中能否用铝制品来盛放食醋？ _________ ，原因是 _________ ；

（3）人们在熬骨头汤时，常常会加入少量食醋，这样做的理由是 _________ ．

以下是水溶性维生素的是（）

A.维生素B

B.维生素D

C.维生素E

D.维生素A

E.维生素K

利用工程的实际沥青混合料级配，按照基层材料击实试验方法进行重型击实试验，击实锤重（），落高45cm，分3层装料，每次击实98次，确定最佳含水率和最大干密度。

A、4.8kg

B、5.2kg

C、4.6kg

D、4.5kg