Have to

Have to (objective obligation)

We often use have to to say that something is obligatory, for example:

• Children have to go to school

Structure of Have to

subject + auxiliary verb + have + infinitive (with to)

Look at these examples in the simple tense:

	subject	auxiliary verb	main verb have	infinitive (with to)
+	She		has	to work.
-	I	do not	have	to see	the doctor.
?	Did	you	have	to go	to school?

Use of Have to

In general, have to expresses impersonal obligation. The subject of have to is obliged or forced to act by a separate, external power (for example, the Law or school rules). Have to is objective. example:

• John has to wear a tie at work.

We can use have to in all tenses, and also with modal auxiliaries. We conjugate it just like any other main verb. Here are some examples:

	subject	auxiliary verb	main verb have	infinitive
past simple	I		had	to work	yesterday.
present simple	I		have	to work	today.
future simple	I	will	have	to work	tomorrow.
present continuous	She	is	having	to wait.
present perfect	We	have	had	to change	the time.
modal (may)	They	may	have	to do	it again.