Scientists have not been able to cure AIDS, _______ any vaccine against the disease.

_______ the room been cleaned yet?

All of them hope that everything will be ready in _______

Peter was the last person _______

_______ flower gets its smell from _______ oil that the plant produces.

“_______,” the doctor advised his patient.

I have just bought a cottage by _______

Peter went _______ the man and asked him the best way to get _______ town.

_______ the question asked by the campus authorities.

The audience were very _______ by her _______.

Barbara asked me _______ her homework that afternoon.

You _______ to do the homework or the teacher will punish you.

National Parks are usually located in places where have been largely undeveloped, and are often with exceptional native animals, plants, and unusual geological features.

Oceans, that cover about 70% of the Earth’s surface, contain approximately 97% of the Earth’s water supply.

The invention of cars makes transportation many easier, but it is cars that are the greatest  contributor of air pollution.

Because an insufficient amount of protein in the diet can cause illnesses, it is imperative that our diet containing an ample amount of the essential proteins.