‘One might get one’s Greek from the very lips of Homer and Plato,’ the Very Young Man thought. ‘In which case they would certainly plough you for the Little-go. The German scholars have improved Greek so much.’
(From The Time Machine by H.G.Wells)
According to the OED, to plough is to fail an examination; and Wikipedia says that the Little go was an examination, actually called Responsions, that used to be required to obtain a degree at Oxford University. Then the sentence means that even if you learnt Greek from the ancient Greeks themselves you wouldn't pass a Greek exam in the late 19th century, because "the German scholars have improved Greek so much".
It looks like that was also asked and answered before at wordreference.