压力容器常见结构形状有()
A、球形
B、圆筒形
C、箱形
D、圆锥形
E、棱形
参考答案:A, B, C, D
— Do you know why the teacher asks for me ?
— He wants you to _____ your absence last night. [ ]
A. account for
B. call for
C. send for
D. reach for
以下树种,冬季开花的是()。
A.梅花
B.桂花
C.海棠
D.广玉兰