问题描述：
1.Several new underground lines______to welcome the World Expo in Shanghai recently.
A.have been built B .were built C.are built D.will be built
2.We______eight English songs in the hobby group by the end of last month
A.have learned B.learned C.had learned D.would learn
要答案还有原因
A.have been built B .were built C.are built D.will be built
2.We______eight English songs in the hobby group by the end of last month
A.have learned B.learned C.had learned D.would learn
要答案还有原因
问题解答：
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