Unless you study harde,you will not pass the examination
You didn't pass the exam because you didn't harder
You passed the exam because studied harder
You will fail the examination if you don't study harder
You study harder,but you won't pass the exam
Of the three sisters,Anna is the least beautiful
The other two sisters are more beautiful
Anna is as beautiful as the other two sister
The other two sisters are less beautiful than Anna
Anna is more beautiful than one of her sisters