Write a sentence with if ... for each situation. Use a type 2 conditional.
We haven't got a calculator, so we can't work this out quicker.
A.We had a calculator if we could work this out quicker.
B.If we could work this out quicker, we had a calculator,
C.If we didn't have a calculator, we could work this out quicker.
D.If we had a calculator, we could work this out quicker.