When we speak, we use ‘contracted forms’ or short forms such as these:
can’t (for can not or cannot)
I’d (for I would or I had)
she’s (for she is)
Notice that contracted forms are also written with an apostrophe to show a shortening of the spelling of not, would, or is as in the above example. Writing a diary is like speaking to oneself. Plays (and often, novels) also have speech in written form. So we usually come across contracted forms in diaries, plays and novels.
I’ve = I have 2.
We have seen that some contracted forms can stand for two different full forms: I’d = I had or I would