B4

Some of the natural wonders are known for their beauty. The Meteor Crater is not one of them. It looks like a big hole in the desert. It ______ by a meteorite hitting the earth thousands of years ago.

CAUSE

B5

The crater is 4,145 feet across, and 570 feet deep. It is the ______ impact crater in the entire world.

LARGE

B6

When Europeans discovered it in 1871, they ______ it was the top of a volcano.

THINK

B7

Since then, scientists ______ the crater for many years, but there are still many secrets and mysteries hiding inside it.

EXPLORE

B8

 I One day last summer my nine-year-old daughter went off to the camp. All her things ______ in a small bag.

PACK

B9

Two weeks later, Anna came back home and I unpacked her things. Everything was clean and well folded. “Camp sure has changed you. Your things look much ______ than usual.”

GOOD

B10

“It was simple, Mom,” she answered. “I didn’t unpack. Many ______ did the same.”

CHILD