理智动机即经过（）思考而产生的购买动机。
A、激情
B、理智
C、战斗
D、波动
参考答案：B
---- What’s wrong with him?
---- He doesn’t feel very well. The doctor _______ just now.
A．looked him over
B．looked him up
C．looked after him
D．looked for him
当后悬挂弹簧和阀联接杆压缩时，下列哪个阀打开，让更高的液压进入后轮制动器分泵？（）
A.压差阀
B.高度感应比例阀
C.比例阀
D.计量阀
