按其在单位时间内所能输出的油液体积是否可调节，液压泵分为（）泵和变量泵两类。
参考答案：定量
凡失去控制并对财物和人身造成伤害的燃烧现象都为（）。
A、爆炸
B、燃烧
C、火灾
D、闪燃
Tim is in good shape physically（）he doesn't get much exercise.
A. if
B. even though
C. unless
D. as long as
