Alexander’s engineers built floating rafts for the heavy catapults.

亚历山大的建了浮动的筏子来运载沉重的弩炮。

Roger Gauthier, a hydrologist with the U.S.Army Corps of Engineers said even heavy snowfall in January and February may not be enough to replenish the water lost.

美国处的水文学者RogerGauthier说一二月的大雪都足够补充五大湖失去的水。