________ pencil cases do you have?—One. [ ]

Where is your sister, Dick? I need her help. — Dad, she in her room. Let me help you instead.

Listen！Helen is singing in the next room.—It _____be Helen .She has gone to Beijing.

A low-carbon(低碳) lifestyle has an effect our daily life. People are paying more and more attention to energies these days.

What does Linda do weekends?[ ]