题目

The baby stopped crying though she understood ________ of what her mother was saying. A.a little      B.little      C.a few     D.few 答案：B某以汽油为燃料的观光汽车沿该盘山公路（盘山公路近似处理为斜面）以36Km/h的速度匀速行驶，经过15min从山脚到达山顶；汽车上山时沿路面获得的牵引力恒为9.2×103N．该汽车的效率为30%，汽油热值q=4.6×107J/Kg，求：（1）汽车上山时行驶的路程是多少米？（2）汽车上山时牵引力的功率为多大？（3）汽车从山脚到山顶消耗了多少千克的汽油？