Choose the correct tense of verb

Listen! I _________________ (think) someone _________________ (knock) at the door.

The Earth _________________ (circle) the Sun once every 365 days.

Mrs. Green always _______________ (go) to work by car, but this week she ____________________ (travel) by bus.

We __________________ (not/know) why Sarah is upset, but she __________________ (not/speak) to us for ages.

“Sorry I’m late.” “That’s all right. I _____________________ (not/wait) long.”

The number of vehicles on the road ______________ (increase).

Why _____________________ (you/stare) at me? I suppose you _______________ (not/see) a woman on a motorbike before!

How many times _________________ (you/see) him since he went to London?