Have To and Don't Have To

have to = external obligation; don't have to = no need.

Examples

• I have to work.
• You don't have to come.

Key rules

• have to shows obligation from rules or situations
• has to for he, she, it
• don't have to means it is not necessary
• Questions and negatives use do/does

Common mistakes

• She have to go → She has to go
• You mustn't come (not needed) → You don't have to come