有关超声的原理，下列哪项正确A．B型超声诊断法即幅度调制型 B

搜题请搜索小程序“爱下问搜题”

问题单项选择题

有关超声的原理，下列哪项正确

A．B型超声诊断法即幅度调制型

B．B型超声诊断法即辉度调制型

C．B型超声诊断法即时间运动曲线

D．B型超声诊断法利用的是多普勒效应

E．B型超声诊断法即等深显影技术

答案

参考答案：B

解析：[解题思路] B型超声诊断法从原理上讲属于辉度调制型。

填空题

缺词填空。

School education(教育) is very important and useful. Yet no one can l 1 everything at school

and a teacher can’t teach his students e 2 they want to know. His job is to s 3 his students how

to learn. He teaches them how to read and how to think. So the students can learn much more by t 4 .

It is more i 5 to know how to study by oneself. It’s quite easy to learn something, but it’s difficult

to u 6 it to solve problems. Great inventors do not get everything from school, but they still can invent many things and change the world a l 7 .

How can the inventors do all of this? That’s b 8 they know how to study. A lot of things are not

taught in the classroom. They get a lot of knowledge by reading o 9 school. They work hard and

never g 10 up all their lives.

多项选择题

下列事项中，村民委员会必须提请村民会议讨论决定的有（）

A．村公益事业的经费筹集方案

B．村公益事业的建设承包方案

C．村民的承包经营方案

D．宅基地的使用方案