Question

But even to the trained eye, two species of earth

But even to the trained eye, two species of earthworms can be tough to tell apart.
可是，即使是受过训练的眼睛，也可能很难把两种蚯蚓分辨开。
eye是不是应该加s啊

Answer 1

在这里，eye虽然可翻译为眼睛，但实际上指的是眼光、鉴赏力等。根据习惯用法，貌似用复数的少。

eye N-COUNT

眼光;眼力;鉴赏力 You use eye
when you are talking about a person's ability to judge things or about
the way in which they are considering or dealing with things.

例句：

William was a man of discernment, with an eye for quality...

威廉是个有鉴赏力的人，对于品质的优劣很有眼光。

Their chief negotiator turned his critical eye on the United States...

他们的首席谈判代表以批判的眼光看美国。

It did not take his practised eye long to notice that he was not the only one who was hanging about...

眼力老道的他很快就注意到他不是唯一在闲逛的人。

Answer 2

对

追答

把but even to改成though 或者although哀家好

Answer 3

要加的，复数

Answer 4

嗯，两只眼睛

Answer 5

是的。

Answer 6

是啊