In the past few months, the country _____ a further tightening of supply restrictions, making fuel and food supplies more difficult to obtain.

As soon as the children _____ themselves in their seats in the classroom, the bell rang.

 The geography teacher told his student that the earth ________around the sun .

Shanghai, China’s biggest and the most dynamic city, which______ in the Yangtze River Delta, is playing a leading role in the country’s economy. 

—I took a picture of you just now.—Really? I______with attention.