If an aerosol counter is used to monitor the concentration of particles in the emerging air, one finds that the concentration falls off with decreasing flow rate . 如果用一台气溶胶计数器检测射出气流中的粒子浓度，就会发现浓度随流速的降低而减少。
At its northern, or nearest end, it was bounded by an isolated mountain, lower land falling off east and west, gracefully relieving the sweep of the outline . 北面，即最近的一端，一座孤山拔地而起，山的东西两侧则是一抹低地，把大地点缀得婀娜多姿。
You ' ll break your neck if you fall off the roof 你要是从屋顶上跌下来会摔死的。
Ripe apples are beginning to fall off the trees 成熟的苹果开始从树上落下来了。
Ernie ： he fell off the monkey bars last week 尔尼：他上星期从单?桥上摔了下来。
Attendance at my lectures has fallen off considerably 听我讲课的人已大大减少了
Just fall off my gorramn ship for no apparent reason 就从我们飞船掉下去了吗？
If i fell off tomorrow would you still love me 如果我没有明天，你是否依然爱我？
Jalu has forgotten falling off hi * icycle 詹露早忘掉他从白行车上摔下来这件事了。
J alu has forgotten falling off his bicycle 詹露早忘掉他从白行车上摔下来这件事了
