—The air in Nanjing was much better during the Spring Festival because people were not allowed to let off firecrackers. —I agree. Everyone should do what he can the environment.
–– When did they arrive? –– They ______two hours ago .They ______ here for two hours .
----It’s important_____ a foreign language. ----I agree with you. We should study hard.
I ______ to think their jobs were ______ .
The maths problem is ______ hard for us ______ solve.
The girl was seenthe piano at 4.00 yesterday afternoon.