列车运行图按照列车之间运行速度差异可分为（）.
A、平行运行图
B、非平行运行图
C、连发运行图
D、追踪运行图
参考答案：A, B
采用张力架线方式进行架线施工时，线材不计人力运输。采用一般架线时，线材计算人力运输费用。
Though Betty doesn’t like her present job, she wants to ______ it until she gets another one.[ ]
A. hang on to
B. hang off to
C. hang up to
D. hang back to
