爱华网at sea，by sea, on the sea, by thesea 的区别
(1) atsea表示“在茫茫大海上”，意指“离海岸很远”。如:
① Now his ships were allat sea. 现在他的船都出海了。
② The ship hit an icebergand buried at sea.这船撞上了冰山，葬身海底。
③ Several ships were lostat sea owing to the hurricane. 由于飓风，好几艘船在海上失踪。
④These sailors were at seafor forty days before reaching land.这些水手在海上漂泊了40天后，他们的船才靠岸。
⑤ Afterthree days at sea we sighted the land.在海上航行了三天，我们终于看见了大陆。
⑥Thispainting is a representation of a storm at sea.这幅画表现的是海上风暴。
⑦ The shiphas spent three months at sea.轮船已在海上度过了三个月。
(2) atsea前面加上all或completely时，引申为“茫然不知所措”之意。如:
①I'm all at sea. I can't understand thatproblem.我简直是一片茫然，我无法理解这个问题。
②He was all at sea when he began his new job.他开始新工作时，茫然不知所措。
③Would you please explain it again? I'm all atsea.你能否再解释一下?我一点儿也不懂。
④The girl was completely at sea when her mother scolded her.当母亲责怪她时，女孩茫然不知所措。
9316;He felt completely at sea in his new school.他在新学校中感到茫然不知所措。
⑥I'm all at sea.我一点主意也没有。
（3） 请注意by sea与by thesea的区别，前者表示“经海路”，后者表示 “在海边”。如:
bysea表示“经海路”； by the sea表示 “在海边”
① "How did you go there?By train?" "No, we went there by sea."“你们怎么到那里去的?乘火车?”“不，我们乘船去的那里。”
③I'm terrified of flyingI'd rather go by sea.我害怕坐飞机--我宁愿坐船.
④May I ask if you are fondof traveling by sea?我可以问一下你是否喜欢海上旅行？
⑤ The Turners lived by thesea. 特纳一家住在海边。
（4）注意go to the sea与go tosea的区别，前者意为“去海滨”(度假或野餐)，后者表示“去当水手”。如:
①Last Sunday, the students in Class Two went to thesea.上星期天，二班的学生去海边玩。
②"I want to go to sea when I grow up." said the boy to his mother.这小男孩对母亲说：“我长大了要去当水手。”
（5）on thesea: a. 在海上(在海面上)
例句与用法:
①The sunglared on the sea.太阳在海上发出令人目眩的光芒。
②There arethousands of awnings on the sea beach.沙滩上有许多遮阳篷。
③The minefinally came to rest on the sea bed.那水雷最后沉入海底.
