3rd conditional

[jkl]

If the children had worn the seat belts the accident would not have had that much.

Is it a correct 3rd conditinal sentence?

Thanks

[g-at-bbe]

If the children had worn the seat belts the accident would not have had that much. (...that much what??)

Is it a correct 3rd conditinal sentence?

Thanks

The main problem is not your use of the conditional, which seems to be structurally correct. Note, however, that most Americans would use the past perfect continuous in the first clause, plus we normally use possessive adjectives in reference to wearing seat belts in a car: "If the children had been wearing their seat belts..."

The problem is that your sentence doesn't make any sense because you failed to tell us what it is that the accident wouldn't have had that much of.

Something like this would be more natural:

"If the children had been wearing their seat belts, they wouldn't have been injured."