灭掉辽和北宋的少数民族 * * 是[ ]
A．契丹
B．氏族前秦
C．金
D．西夏
答案：C
The last time we had great fun was _____ we were visiting the Water Park. [ ]
A. where
B. how
C. when
D. why
并非所有公文都具有领导与指导作用。（）
