I am, you are... — "to be" in present simple positive
I am not, you are not... — "to be" in present simple negative
Am I? Are you? — Present simple questions with "to be"
Present perfect vs. Past simple
You had left before I came — How to use past perfect
Present simple and continuous for the future, to be going to
Passive voice (I was told)
At 2 o'clock on Sunday — Prepositions of time