—Why do you walk to school today?—Because ________.
English is _________ international language.
We'll hold a party in celebration of the 90th birthday of the CPC (中国共产党) _________ Friday. A. in B. on C. at
—Miss Zhou is very popular with the students. —Yes. Her classes are_________ lively and interesting. A. always B. sometimes C. hardly
Mrs. Weng came back from France in 2010. She _________ there for four years. A.works B. worked C. has worked
—Do you know the song Come on, Haixi!—Yes, and I _________sing it well. A. must B. can C. need