Concentrations of 10 ppm can be endured for only a few minutes and cause profuse lacrimation in all people . 10ppm的浓度，只需几分钟，就会使所有的人流泪不止。
Here a more "elegant" method will be used, which will supply the same information in fewer steps . 这里将使用一种更巧妙的方法，只需要很少几步就提供相同的信息。
Since sound waves are longitudinal, only one dimension need be considered to obtain the sound wave solution . 由于声波是纵波，所以为了得到其解，只需考虑一维就行了。
Neither of our two adventurers used his paddle, except to keep the light bark in the center of the current . 我们的两位冒险家只需让轻舟不偏离河中央，再也不用动桨了。
You've only got to bottle up your rapture, and keep beth quiet till that blessed lady gets here . 你呢，只需按捺住自己的欢喜，使蓓丝保持安静，坐等那个神圣的夫人回来吧。
It is sufficient to map each on a circle and then a product of two conformal mappings will do the trick . 只需将每一区域映射到一个圆，然后做两个保形映射的乘积就可达到目的。
I feel if i have him under my roof, a, he's safer, and b, it is only costing one lot of security . 他同我住在一起，我认为有两个好处，一是他更加安全，二是只需在一处采取安全措施。
When we shall once know these zones, we shall only have to place the balloon in the one that will suit us . 将来我们了解了这些空气层以后，就只需把气球置于对我们最有利的空气层里了。
In deducing the motion we will need to concern ourselves only with the component of angular momentum related to this axis . 在分析这种运动时，我们只需涉及在该轴方向上的角动量分量。
At some intersection drivers must come to a completestop; at others they are only required to slow down . 在有些交叉路口，司机必须把车完全停住。而其他位置，他们只需放慢速度就可以了。
