—Why didn’t Tom go to the concert last night ?— I have no idea,but I think he _____ in his study.
The computer looks old, but it _________ just half a year ago.
The art centre is _____ used to be a factory, _____ millions of tractors were made.
The coach asked his staff to_____the large group of journalists waiting for him to announce his training plans.
With the price of ______ petrol rising, the bicycle may become ______ popular means of transportation again.
________all kinds of difficulties,the workers have made rapid progress in the construction of the World Expo 2010 Shanghai.