1. Walking home is not a good idea.
-> If I were you, I wouldn't walking home.
2. Throw a stone into water and it sinks.
-> If you throw a stone into water, it sinks.
3. Don’t take this job if you don’t really want it.
-> Unless you really want the job, don't take it
4. Be faster. Otherwise, they will catch you.
-> If you aren't faster, they will catch you.
5. Work hard, or you will fail the exam.
-> You must work hard if you don't want to fail the exam.
$_Study well_$