What is the central idea of the passage “thermometer pills

Clarification:

I found the complete instructions for the exercise online:

Rewrite the following passages filling in the blank spaces with suitable linking words from the lists given at the end of each passage. [what, and, also, that, which]​

One of the most wonderful inventions of modern times is television. It is now possible to sit in the comfort of ones home and watch on a screen events which are happening hundreds of miles away. We can also get entertainmen from films, dances,plays and sports that are shown on the screen. It is difficult to imagine what life would be like without television.

Explanation:

In this exercise, you have to complete the text given with different linking words.

Linking words are words that are used to connect different ideas or arguments.  In this case, the text is about television and how it changed the way we entertain ourselves.