中国节能减排徽标上有8个字，为节能减排，（）。
A.从我做起
B.人人有责
C.全民行动
参考答案：C
影响时间数列变动的因素主要有（）。
A.长期趋势
B.季节变动
C.循环变动
D.不规则变动
- Has John arrived yet?
-- No, she _______ an hour ago.
A．was supposed to come
B．must have come
C．should come
D．ought to have come
