did, didn’t, use to, used to.

What did people _____ do to keep in touch?

• use to
• used to

In the past, people ______ write emails.

• didn't use to
• didn't used to

What ______ people use to do to cook their food?

• do
• did

Long ago, people didn't ______ cook in microwaves.

• used to
• use to

What _____ people use to do to travel?

• didn't
• did

In the past, people _____ travel by horse and buggy

• used to
• didn't used to

What did people______ to do to call each other?

• use to
• used to

100 years ago, people______ have cell phones.

• didn't use to
• used to