The explorers put on gloves and boots the last.

The difficulty means the difficulty of going inside the cave.

With special clothes, people can stay in the cave for days.

I’m still hungry. I didn’t eat __________ food at lunchtime.

Dr. Rogers was busy writing an article, so he did not want any __________ to come to his home.

I’m going to ________ a suit for my job interview tomorrow.

You will get to school faster if you walk __________ the field rather than around it.

Some people believe the skulls help people.

Most of scientist think Mesoamericans might have made the skulls.

Most of scientist think humans need modern technology to make the skulls.

Most scientists think the skulls have a speacial powers.

There are marks on the skull.

Most of scientist think archeologists have not found a crystal skull during an excavation.

Scientist today are _________ that the earth is round.

Some people can't have a ________ without getting angry.

Archeologists look for _________ to show they are correct.

All humans have the _________ to learn languages, but some people are better at it than others.