根据短文内容，选择正确答案。

　　Hi, I'm Paul Smith.  Paul is my first name.  Smith is my last name.  I like

red.  Look! This is my ruler. It's red. And this is my pen. It's red, too. This is my

brofher Bob. He is ten years old. He likes white and black. Look! That is his

pencil. It is black. And that is his pen. It's white.  This is my father Mr Smith. He

is an English teacher. He likes green. His pen and ruler are green.

1. Paul's brother's_________is black.

A. watch    

B. pencil    

C. ruler    

D. pencil case

2.  Paul's brother likes________.

A. red    

B. green    

C. black and white    

D. blue

3. Paul's ___________ likes green.

A. sister    

B. mother    

C. brother    

D. father

4. —Is Paul's ruler red?

    —_____________．

A. Yes, it is    

B. No,it isn't    

C. Yes, it isn't    

D. No, it is

5. —Smith is Paul's

    —_______________.

A. first name    

B. last name    

C. color    

D. sister

下列超声波中，最易导致空化效应的是（）。

A.高频加低强度

B.高频加高强度

C.低频加高强度

D.高频

E.高强度