列车运行图按上下行列车数量不同分为（）。A、平行和非平行运行

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问题单项选择题

列车运行图按上下行列车数量不同分为（）。

A、平行和非平行运行图

B、单线和双线运行图

C、成对和不成对运行图

D、连发和追踪运行图

答案

参考答案：C

选择题

( ) 1. Jack lives in Sydney.	A.
( ) 2. His father goes to work by subway.	B.
( ) 3. His father teaches math in a school.	C.
( ) 4. His grandpa reads newspapers every day.	D.
( ) 5. Jack always goes to bed at 9: 30 pm.	E.
( ) 6. His sister likes playing the violin.	F.

单项选择题

铁法的氧载体大多使用（）。

A、二价铁

B、三价铁

C、五价铁

D、六价铁