The ancients well understood the usefulness to commerce of connecting the Red Sea with the Mediterranean, but they never dreamed of cutting a canal between the two, and instead they picked the Nile as their link.

古时人明白，在红海与地中海之间建立交通，对于他们业有好处，可是他们没有想到发掘一条直通运河，他们是利用尼罗河来作居间。

Sometimes the intermediate degrees may be lexicalized.

有时居间程度可能被词汇化了。