求助一个长句

lzhch89 · 发表于 2011-4-7 08:19:13

Because the vertical pressure gradients within the blood vessels
are counteracted by similar pressure gradients in the
surrounding water, the distribution of blood
throughout the body of sea snakes remains about
the same regardless of their orientation in space,
provided they remain in the ocean.

OG的一篇阅读，句意读是明白了。NN能不能解释一下provided they remain in the ocean 在句子里的成分。不明白为什么要用they。如果要用they感觉provided和they应该不是一句话存在的。如果一句话，应该用them宾格吧。但是往前找provided的主语，也没发现。

求助一个长句

所属分类: GMAT考试

正在浏览此版块的会员 ()

浏览过的版块