We use "to" because we wnat to use two verb in a sentence but a sentence cannot have two verbs so we use "to". then we can use one more verb.

Carl Sagan

Carl Sagan's invention is Big Bang. It is talk about the space.

I like playing the piano most because playing piano can calm down myself. When you are playing it, you will fall in the music. It feels good. I like palying most but I hate practising the piano too. I hate practising because I am lazy.

The lower hall isn't very big but
we can do many activities in it.
(Each line five beats.)