to write a letter
1) I, you, we, they write a letter; he, she writes a letter
2) I, you, he, she, we, they wrote a letter
3) I, you, he, she, we, they will write a letter
4) I`m, you are, he is, she is, we are, they are writing a letter
5) I was, you were, he was, she was, we were, they were writing a letter
6) I will (shall) be, you will be, he will be, she will be, we will (shell) be, they will be writing a letter
7) I have, you have, he has, she has, we have, they have written a letter
