Can anyone define these quotes from george orwell's 1984?

The first one is saying that dying is definite if you think bad things against the government, the second is saying that in this place and time, the most dangerous thing you can do is simply to think, because it can make you show emotion other than the ones the government wants you to feel, which is also leading to death, and the third one is saying that everyone has to be sane in this society.