Hi there!
For number 46, the original sentence is grammatically correct. If you wanted to add a word, you could say "...in a confusing past that many PEOPLE realize bears little..."
For number 52, Are you asking if "false" is correct to use here?
It is okay for the writer to write "false", since the exercise talks about family members lying to their loved ones in order to create a fake reality for them. Knowing the "true" reality would hurt them.
For number 55, "simply" is used for emphasis of one specific point, similar to "just".
"finally" can be used for emphasis, but it's usually when something has taken a very long time to happen, and when it does there's a sense of relief (ex: after trying for hours, we finally solved the problem).
In this example, "simply" is the correct answer.
I hope that helps!