I just don’t understand _____that leads to so many teenagers becoming addicted to playing computer games. [ ]

I’m sorry I _____________ you__________ tome

It was not until the 18th century that man realized that the whole of the brain was involved in the working of the mind，　　　　？

My daughter studies______. She _____goes tosleep before 11 o’clock at night.

How _____ I was when I heard the ______ news!