- The contracted form of have.
- I've tried everything to make the car start, but it will not!
- I need $100, but you've only $50 to give me.
In the US and other places, they only use the contraction ' 've ' when the word 'have' is helping another verb go into the perfect aspect. An American might say the first example above, since 'have' is an auxiliary to the verb 'tried.' An American might not say the second, one since 'have' is a verb by itself. Some people proscribe examples like the second one--they think people should not say them.