6. Nam/ had better / not / smoke / because /it/ bad / for / health.
=> Nam'd better not smoke because it is not good for  health
7. You/have/ study hard / if/you/ want / pass/all/your exams.
=> If you want to pass your exam, you must study hard

Nam had better not smoke because it is not good for  health.
If you want to pass your exam, you must study hard.

6.Nam had better not smoke because it is not good for  health.
7.If you want to pass your exam, you must study hard.