儿童的骨柔韧有弹性、不易骨折,但易变形,原因是骨成分的含量（_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题选择题

儿童的骨柔韧有弹性、不易骨折,但易变形,原因是骨成分的含量（）

A．有机物约为2/3，无机物约为1/3　　

B．有机物约为1/3，无机物约为2/3

C．有机物多于1／3,无机物少于2／3

D．有机物少于1/3，无机物多于2/3

答案

答案：C

题目分析：骨的成分包括有机物和无机物，有机物越多，骨的柔韧性越强，无机物越多，骨的硬度越大；在不同时期，骨的成分不同，如下表：

所以在儿童青少年的骨中，有机物多于1/3，骨的弹性大，容易变形，所以青少年要注意坐、立、行的姿势。故选：C

阅读理解

阅读短文，选择正确答案。

Sam and Tom are twin brothers. They are ten. They are in the same school. They are in Class l, Grade 4.

They're in the same coats and trousers. They have the same school bags. Sam has a new pen. But Tom's pen is

old. Tom has a new pencil box. But Sam's pencil box is old.

1. Sam and Tom .[ ]

A. are twins

B. are sisters

C. like their schools

2. How old are they?[ ]

A. They're twelve.

B. They're eleven.

C. They're ten.

3. What class are they in?[ ]

A. Class 1, Grade 3.

B. Class 1, Grade 4.

C. Class 4, Grade 1.

4. What are the same?[ ]

A. Their pens.

B. Their coats.

C. Their pencil boxes.

5. What are different?[ ]

A. Their schoolbags.

B. Their trousers.

C. Their pens.

单项选择题

关于慢性肺心病心衰应用洋地黄治疗的叙述，错误的是（）

A.应用前需纠正缺氧

B.应先抗感染治疗

C.心衰纠正即停用

D.用小剂量快作用制剂

E.心率70～80次/min为疗效指征