血清淀粉酶升高最常见于（）
A.十二指肠溃疡穿孔
B.胆囊炎
C.胰腺癌
D.急性胰腺炎
E.胆管梗阻
参考答案：D
He has been working since 7:30 this morning. ______ he is so tired out.
A．It is no wonder
B．It is no way
C．There is no need
D．There is no point
轴承保持架可以避免滚动体之间由于（）而增大摩擦阻力和磨损。
A、接触
B、直接接触
C、窜动
D、撞击
