阈限值
参考答案:
几乎所有工作人员长期暴露都不会产生不利影响的某种有毒物质在空气中的最大浓度。
单词拼写。
1. Chinese history is filled with great ____________(成就) in science and technology
2. She was ____________(满意的) with her birthday presents from her friends.
3. When I came to the riverside, I found a boy ___________(挣扎) in the water.
4. It is our duty to ____________(保卫) our motherland.
5.The four poles, ___________(支撑) the ceiling were well built.
6. He has made several ___________(发现)in science.
7. Children are taught to __________(尊敬)their teachers in the kindergarten.
8."Mind your___________ (行为) , "the mother said to her young boy.
9. I could hear them ____________(私语)under the tree over there .
10. Usually children are ____________(好奇的)about everything they see and meet.
下列对左上叶肺不张的X线表现描述中哪一项是错误的()
A.无气肺叶向前胸壁向上移位
B.后前位胸片上左上中野大片阴影,上部密度较下部密度高
C.下叶背段无变化
D.侧位胸片上无气肺叶向后移动
E.下叶出现代偿性肺气肿