编组站、区段站等配有调车组的线、确有困难时接触线距轨面最低高度不应小于（）mm。 A

掌握好焊接顺序和（）是防止扭曲变形的主要措施。

A、焊缝间隙

B、电流调节

C、焊接方向

D、焊缝宽度

The Customs surveillance zone include the following places except （）.

A. any seaport, railway and high way station, airport, border pass or international postal matter exchange where there is a Customs establishment

B. any place where Customs control is conducted

C. any place without a Customs establishment but which has been approved by the state council as a point of entry and exit

D. any place along the border of the country

什么叫不锈钢？

苔淡黄而滑者主（）

A．寒湿内结

B．热入营血

C．食积化热

D．寒湿化热

E．热盛伤津

进气系统阻力包括（）等部分产生的阻力。

A.空气滤清器

B.进气管

C.进气门

D.进气歧管