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

亚历山大工兵修建了浮来运载沉重弩炮。

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.

美国工兵处水文学者RogerGauthier说一二月大雪都未足够补充五大湖失去水。