钢的机械性能
参考答案：
在静力负荷和动力负荷下钢的强度，塑性和韧性。
The teacher, with 6 girls and 8 boys of her class, ____visiting a museum when the earthquake struck [ ]
A. was
B. were
C. had been
D. would be
设备贷款的期限最长不超过()年。
A.2
B.3
C.5
D.6
