_____ is the envelope? [ ]
A. How old
B. How often
C. How many
D. How much
答案：D
Do you know the reason ______ he was late?[ ]
A. for which
B. for what
C. which
D. that
1996年10美元光变油墨印刷的面额数字在晃动时颜色在绿色与黄色之间变化。
