四、条件（161-200）

161. To the extent that it is real, the interaction with the lower boundary seems a good candidate to explain the high persistence of the system.

如果这一结果可靠的话，那么这一系统与下边界的相互作用似乎可看作解释它长时间继续存在的可靠原因。

162. Two fronts will exist if we have three air masses, a coal, a warm, and a cold, moving from west to east one after another.

如果我们让三个气团（一冷，一暖又一冷的）依次由西向东运动，则会出现两个锋。

163. If the input file exists, then we must create a new output file.

如果该输入文件存在，那么我们必须开辟一个新的输出文件。

164. (According to the weather report, the typhoon will pass over the region)If so, the drought will be relieved.

（根据天气报告称，此次台风将经过这个地区）如果是这样，旱象将得到缓和。

165. If the moon were, for instance, over the site of Miami, there would be a tidal bulge there and also on near the west coast of Australia.

例如，假如月亮在迈阿密测点的上空，那里就会出现海潮的隆升，而在澳大利亚西海岸附近的海面也会出现隆升。

166． If the earth’s axis did not tilt, there would be no seasonal change on it.

如果地轴不倾斜，地球上就没有季节变化。

167. Were there no such superior laws, physics would be impossible as an exact secence over any sufficiently long period.

如果没有这些颠扑不破的定律，物理学就不可能在任何足够长的岁月作为一门精确的科学而存在。

168. If this situation should occur, the fram would become unusable.

如果出现这种情况，框架就成为无用的了。

169. Should the current be cut, the coil would return to its original position.

如果电流切断，线圈就返回到原来位置。

170. Had Franklin known what we know about lightning in those days, he probably would not have undertaken such a dangerous experiment.

如果富兰克林当时与今天我们关于闪电知识的认识一样，他可能不会进行那种危险的（风筝）试验了。

171. If we had not taken necessary precautions, the typhoon would have inflicted heavier damages.

如果当时不采取必要预防措施，台风就会造成更加严重的损害。

172. If it were not for the modern equipment, such experiments would not be performed.

如果没有这些现代化设备，这些实验就不能进行。

173. With the equipment the experiment would be readily conducted.

如果有了这些设备，试验就会顺利进行。

174. Water vapor is lighter, which would otherwise not rise into air.

水汽（比空气）较轻，否则它不会升到空中。

175. Since this frame of reference-the earth –is rotating, motions that would be straight in a stationary frame of reference appear curved to the observer on earth.

由于参照系—地球—是旋转的，所以在静止参照系中应是呈直线运动，在地球上的观测者 看来就成为曲线运动。

176. This is clearly not the case, if it were true, prediction of the tides could have been done for centuries.

很清楚，情况并非如此。假如真是这样，潮汐预报可能已发布几个世纪了（事实并非如此）。

177. Provided we make on further assumption, the Copernican principle leads to a rather similar universe model.liuxuepaper.com