按顺序写出26个字母的小写形式。
a
z
a b c d e f g h i j k l m
n o p q r s t u v w x y z
— ____?
— It's an orange. [ ]
A. What's this
B. What's its name
C. What color is it
D. How is it
试述水筛法检测水泥细度的试验方法。
