Without a visa, he couldn’t have come to that new country.
--> If he had had visa, he could have come to that new country.
Today isn’t Sunday, so the students don’t go swimming.
--> If today were sunday, the students woudl go swimming.
Because you don’t leave immediately, I call the policeman.
--> If you don't leave immediately, I will call the policeman.
I don’t know her number, so I don’t ring her up.
--> If I knew her number, I would ring her up.
Go right now or you will be late for the train.
--> If you don't go right new, you will be late for the train.
As she is often absent from class, she can’t keep pace with her classmates.
--> If she weren't often absent from class, she could keep pace with her classmates.
I couldn’t write to Alice because I didn’t know her address.
--> If I had known her address, I could have written to alice .
The heavy rain kept everybody from going outdoors.
--> If it hadn't rained, everybody could have gone outdoors.
People don’t see the UFO, so they don’t call the National UFO Reporting Center.
--> If people saw the UFO, they would call the .....
Thu can’t swim, so she doesn’t go swimming in Lam Son Swimming pool.
--> If Thu could swim, she would go swimming in.....