喷油器定时是指各缸喷入燃油的时间按照柴油机的（）选择最佳喷火时机。
A、功率
B、发火顺序
C、性能
D、动能
参考答案：B
This is ________ interesting book. [ ]
A. an
B. a
C. the
D. /
--- It’s so hot in the room . _____
--- Not at all . I’d be happy to .
Isn’t it very cold today ?
B Are you feeling ill today ?
C. Would you mind opening the window ?
D.Have you bought the kite to me ?
