用于预应力钢筋混凝土的钢筋,要求钢筋()。
A.强度高
B.应力松弛率低
C.与混凝土的粘结性好
D.ABC
参考答案:D
—Have you seen my brother?
—Yes. I _____ him in the library five minutes ago.
A.have met B. met C.meet
简述肺炎的解剖分类。