My sister ________ to school on Sundays.
—What do you plan to do on the ___________ May Day holiday?—I have no idea. Probably, I will spend it by doing many papers.
—Excuse me, Mum. When can we have dinner?—Not until it in half an hour.
—You see, “Food Safety” receives thousands of Internet hits a day.—Obviously, it has become one of the _________ topics recently.
—Do you know that our school has been named Green Olympic Demonstration School?—Yes. We are all excited ___________ that.
—You look so worried, what’s wrong?—More and more people like me become to worry about the __________ pollution after the haze (雾霾) appeared in Beijing and some other cities in China.