The key answer of exercise 5

Meanings:

1. The more, the merrier → If more people are involved in something. it will be more enjoyable. We often use this expression to say everyone is welcome.
2. The sooner, the better → You should do something as soon as possible.
3. The bigger they come, the harder they fall → If people or things are powerful and successful, they will suffer more when they are defeated. This expression is often used to say you should not be scared because your opponent is big or well-known.