`1.` hadn't behaved
- Câu ước ở QK: S + wish(es) + (that) + S + had (not) + VpII
`2.` hadn't been
- S + VpII + as if/as though + S + had (not) + V2/V-ed/VpII
`3.` If they hadn't made too many mistakes, they wouldn't have failed in the exam.
- If + S + had (not) + VpII + ...,S + would/could/... (not) + have + VpII + ...
Had they not made too many mistakes, they wouldn't have failed in the exam.
- Had + S + not + VpII, S + would have + VpII + ...