我国陆上邻国中，面积最大的国家是_________，人口最多的国家是_________________。
俄罗斯；印度
男，7岁。2年来双侧腮腺反复肿胀，抗感染治疗可缓解，宜进行的检查是（）。
A.CT
B.B超
C.腮腺造影
D.细针吸活检
E.切取活检
Our math teacher ______ in our school for 20 years and he _____ here when he was 23 years old.
A．has taught, has come
B．taught, comes
C．taught, came
D．has taught, came
