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问题 单项选择题

下列关于预应力混凝土结构的说法，何项是正确的（）？（1）预应力混凝土构件的极限承载力比普通钢筋混凝土构件高（2）若张拉控制应力σ相同，先张法施工所建立的混凝土有效预压应力比后张法施工低（3）预应力混凝土构件的抗疲劳性能比普通钢筋混凝土构件好（4）由于施加了预应力，提高了抗裂度，故预应力混凝土构件在使用阶段是不开裂的

A.（1）、（2）

B.（2）、（3）

C.（2）、（3）、（4）

D.（1）、（2）、（3）、（4）

答案

参考答案：B

选择题

胡 * * 同志在十七大报告中提出实现全面建设小康社会奋斗目标的新要求时指出：建设生态文明，基本形成节约能源资源和保护生态环境的产业结构、增长方式、消费模式。强化生态文明观念对于我国经济发展的根本要求是　　

A．实现经济量的扩张，做大经济总量

B．努力降低能耗　　

C．加快实现经济发展方式的转变

D．加大环境保护的力度
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单项选择题

One day while a girl was walking in the woods she found two starving songbirds. She took them home and put them in a small (16) She cared for them and felt great love for them.

Once the (17) and per of the two birds flew from the cage. Therefore, (18) he flew close, she grasped him (19) She felt glad, but suddenly she felt the bird go limp. She opened her hand and (20) in horror at the dead bird.

She noticed the other bird moving back and forth on the edge of the cage. She could feel his great need for (21) She lifted him from the cage and (22) him softly into the air. The bird circled once, twice, three times.

The girl watched delightedly at the bird’ s enjoyment. Her heart was no longer (23) with her loss. Suddenly the bird flew closer and (24) softly on her shoulder. It sang the sweetest melody that she had ever heard.

The fastest way to (25) love is to hold on it too tightly, while the best way to keep love is to give it WINGS!

25().

A.gain 

B.give 

C.lose 

D.show
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