Jeff goes to work ____ and his wife(妻子) goes to work _____.

A．by car…on bike

B．by a car…on a bike

C．by car…on her bike

D．by his car…in her bike

皮带机胶带的拉紧方法有重物拉紧和（）拉紧两种。

A.机器

B.电机

C.人力

D.机械