A:is
B:are
C:am
下列事件按时间先后排序正确的是( )
①战略导弹部队建立 ②中美关系正常化 ③和平共处五项原则 ④“科教兴国”战略
——Shall we go to Alberta for the summer holiday? ——_________. It's one of the world's cleanest cities.
Can you hear a train? Yes.