In the park , the number of the visitors is tightly ____ to avoid damaging the environment or putting stress on the animals.

If you are going to stay in the United States for longer than a(n) ______ visit, you may be interested in learning more about its people and culture.

They eat less sugar and that’s ______ they have ______ white teeth.

These natural parks are very important for preserving many animals, which would _______ run the risk of becoming extinct.

She doesn’t speak ____ her friend, but her written work is excellent.