Translation:This is the thickest book that I have ever read.
I agree that this sentence needs to be replaced. Also the pronunciation of 'baca' is incorrect.
True. From where did they take the pronunciation though? I'm curious.
I agree with thick v fat. Also, in the word-bank style exercise omitting “that” should be accepted. Reported.
But "thick" means "tebal", not "gemuk". The sentence itself is weird though in Indonesian, never heard anyone says fat to indicate a book's thickness. I think the sentence should be replaced to "Ini buku tertebal yang pernah saya baca" (This is the thickest book that I have ever read).