present tense
John owns a Ferrari.
correct
Supposing you found a wallet with cash, would you keep it?
correct
Our team surprised everyone by winning after no one had given them a chance.
correct
We ................... (make) goulash so the kitchen was still hot and steamy when my mom cam in.
had been making
Wendy is all over the place. She has a graduation party tonight.
Incorrect: is having
What were you doing yesterday at eight?
correct
He failed his test because he has not studied.
incorrect: had not studied
If you ................ (come), you could have stayed with us.
had come
The new course is starting in March.
Incorrect: starts
Jim and I had lunch with friends when we heard about their new home.
incorrect: were having
incorrect: have gone
The photo copying machine .......... (break down) several times this week.
has broken down
I think Emma is heading out of here first thing tomorrow.
correct
While he drove, I fell asleep.
incorrect: was driving
He has been calling 4 times and has asked for you each time.
incorrect: has called
My little brothers were filthy because they .... (play) outside all day.
had been playing