无缝钢管直径通常是以（）表示。
A、壁厚
B、外径
C、内径
D、公称直径
参考答案：B
骑士文学及其代表作？
23. Although he offered her a high salary, he could not ____ her to accept a position with his firm.
A．persuade
B．advise
C．suggest
D．convince
