lots of contractions
Contractions two words put together in a shorter form. We use lots of contractions in English: isn't (is not), doesn't (does not), didn't (did not), can't (cannot), won't (will not). I'm (I am), you're (you are), we're (we are). There are tons of them!
But let's (let us!) talk about some tricky contractions. Contractions with apostrophe -s ('s) and apostrophe -d ('d) are difficult because they have two meanings. Think about it: what does he's mean? Look at these two sentences:
He's studying English.
He's visited England.
In the first sentence, he's means he is. In the second sentence, he's means he has. When we see 's it can mean either has or is.
I'd been working for hours.
I'd like a glass of champagne.