___ most of the earth’s surface is covered by water, fresh water is very rare and precious.
The stream________during the hot summer, but it is full of water in spring.
The beggar’s suffering couldn’t arouse any ________ ,who had lost his shirts because of being addicted to gambling.
The old professor has three sons,________are doctors.
Tom ________ two of his classmates ________ invited to the party.
The audience were ________ by his ________ performance on the stage.