by sea, by the sea
这两个词组仅仅相差了一个单词"the"。by sea 意为“在海边”,其中by表示“在......旁边”,by与后面的名词间常有冠词修饰。there is a small village by the sea.海边有个小村庄。
by sea的同义词组是by ship。意思是乘船。