北伐战争时期，先后作为中国革命中心的城市有
①广州②重庆③南京④武汉 [ ]
A．①③
B．①②
C．①④
D．③④
答案：C
— What do you think of teaching, John?
— I find it fun and challenging. It is a job ______ you are doing something serious but interesting. [ ]
A. what
B. which
C. where
D. that
合法的电子邮件地址是( )。
A．chen.em.kuai.con.cnB．em.kuai.tom.cn.chenC．q：m.kuai.com.en@wangD．chen@em.hxig.com.cn
