问答题

有一气缸盖螺栓联接，若汽缸内气体压力在0~2MPa之间循环变化，则螺栓中的应力变化规律为（）。

答案： A.对称循环变应力
B.脉动循环变应力
C.非对称循环变应力
D.非稳定循环变应力
正确答案：非对称循环变应力

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Unit 4 Test Writing
Directions: Read the following paragraph, and analyze the question-example-conclusion pattern. Find the question, example and the concluding sentence.

[1] Some first responders do not succeed in helping others and they get injured or die in their efforts. [2] Do these people become heroes because of what happens to them as they try to help others – instead of what they actually make happen? [3] Eleanor McMahon was sure that Sgt. Russell was indeed a hero because he showed distinct courage when trying hard to stop the snowplow before it hurts others. [4] She strongly argued: it’s natural for people to rush toward safety and away from danger. [5] But heroes rush toward danger to help those in need. [6] We expect first responders to rush forward, especially when we or our loved ones are in danger. [7] So when they die doing that, we should recognize their heroic efforts.

(1)1. Which sentence is the “Question” ?
A. Sentence 1
B. Sentence 2
C. Sentence 4
D. Sentence 7

(2)2. Which sentences are “Examples”?
A. Sentence 2-3
B. Sentence 3-5
C. Sentence 4-6
D. Sentence 4-7

(3)3. Which sentences are “Concluding sentences”?
A. Sentence 1-3
B. Sentence 2-5
C. Sentence 6-7
D. Sentence 4-7

答案：填空(1)： B 。填空(2)：正确答案 B ...

单项选择题

创编健身健美操时，一定要讲究（）
A 全面性
B 针对性
C 科学性