Native speakers aren't robots! Here are some commonly used expressions and idioms in English.

English Idioms

Lots of different things.

"There were a whole host of different activities to do."

To learn a new skill or habit without meaning to.

"I picked up French whilst travelling in Paris."

To achieve two things at once.

"I kicked the football back to my neighbour and he calmed down, so I killed two birds with one stone!"

To be boring.

"Maths class is such a drag."

To explain something correctly.

"That is exactly what I meant, you hit the nail on the head!"

To watch over somebody.

"I'm keeping an eye on her whilst she plays in the park."

To keep an eye on someone/to keep an eye (verb)

To attempt an activity that is too challenging.

"I am very scared of heights, so I have bitten off more than I can chew."

To be excited, happy.

"I was over the moon when he asked me to marry him!"

To study.

"I'm going to hit the books to prepare for my exam."