Modal verbs

[Unregistered]

It's necessary to delete incorrect modal verbs:
a. We ..... (mustn't pay) now but we can if we want. ( mustn't pay/don't have to pay/ haven't got to pay)
b. I ... ( needn't take) my laptop, so I left it at the office. (needn't take/didn't need to take/needn't have taken)
c. We ..... (needn't have waited) if we'd known he wasn't coming in today. (didn't need to wait/mustn't wait/needn't have waited)
d. When I was a student, I.... for hours on end. ('d study/would have studied/used to study)
e. I .... (would be) quite left-wing, but I've become more conservative. (used to be/would be/must have been)
f. She..... (won’t have left) by now-it’s after twelve. (should have left/’ll have left/won’t have left)
g. I took my driving test three times before I.... (was able to) pass (could/was able to/managed to)

[jlinger]

a. We ..... (mustn't pay) now but we can if we want. ( mustn't pay/don't have to pay/ haven't got to pay)

Depends on what you want to say.

If it's a bad idea to pay now (perhaps you won't be able to get a refund if you do) then we mustn't pay now, or shouldn't pay now.

If, however, you can pay now, or later, as you please, then you don't have to pay, or needn't pay now ("haven't got to pay" is standard lower class English....).

Using this illustration, do you still have questions on the remaining examples? Or should we finish your assignment for you?