Don’t trouble trouble ________trouble troubles you.
— How clever you are! How can I know as much as you?— ______ you read, _______ you can learn.
Young people think it _____ great fun to surf_____ Internet.
The teacher asked the students .
Alow-carbon(低碳)lifestyle has an effect our daily life.More and more attention has been paid to Energies these days.
The teachers _________ the office for a few minutes when we arrived.