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【单选题】
主拱圈是拱桥的重要承重结构，沿拱轴线可以做成等截面或变截面的形式。根据主拱圈截面形式不同可分为板拱、肋拱、（）和箱等。A.
钢管拱
B.
实腹式拱
C.
空腹式拱
D.
双曲拱
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举一反三
【简答题】A．He was attracted by Mrs Jones. B．He had heard a noise. C．He had run out of gas. D．His tyros were punctured.
【单选题】指出句中状语:Every night he heard the noise upstairs.
A.
every night
B.
heard
C.
the noise
D.
upstairs
【简答题】Frank was a poor man, so he tried to grow ______1_______ he could in his own garden, so that he would not have to buy so many in the market. One evening he heard a noise in his garden and looked out o...
【简答题】"Frank was a poor man, so he tried to grow 1 he could in his own garden, so that he would not have to buy so many in the market. One evening he heard a noise in his garden and looked out of the window...
【单选题】在钙磷代谢的调节中甲状旁腺激素的作用是
A.
升高血钙、降低血磷
B.
升高血磷、降低血钙
C.
增加肾小管对钙、磷的重吸收
D.
减少肾小管对钙、磷的重吸收
E.
增加血中钙、磷浓度
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