下列组织中对传入的超声衰减最小的是（） A.肌肉 B.脂肪 C.骨骼 D.血液 E.
题型：单项选择题
问题：
下列组织中对传入的超声衰减最小的是（）
A.肌肉
B.脂肪
C.骨骼
D.血液
E.气体
题型：单项选择题
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| As students we should learn to help others. There is a special 1 for us to help others at our school. Last year we went to an old man's 2 , and we sangsongs, danced and didhousework for 3 . The old people were very 4 . And on that day we felt very excited 5 we can try our best to do good things forpeople. I think we should do things like thatmore often. For example, we should 6 primary schools and help the teachers 7 young students .I want to be a 8 when I'molder, so it would be a great experience for me. 9 students would like to do other jobs. Forexample, my friend Liu Lei wants to 10 for a newspaper. She usually goes to the newspaperoffice once a week.  | ||||
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