Well, using my limited knowledge, "cleaving" means to chop, break in half, split, etc. Twain means twice. So, perhaps it's like "you've broke my heart in half", something along those lines? hopefully this helps you.
I think you’ll find this funny
They were walking through the hall and she fell down on someone sat on them and fell back....
The information about the Luggnaggians which the narrator
(Gulliver) offers to his audience (English people) is their traditional
customs. At some fact of the story, Gulliver gives his view on the way to
points of views of Luggnaggians by telling it in order to make his spectators
learn the conceivable errors of others and not to do it again.
