问题
选择题
As _____rule, apples are sold by_______weight and eggs by _______dozen.
A．a; 不填；the
B．a; the; the
C．a; a; the
D．the; 不填；不填
答案
答案：A
as a rule(通常地)是固定词组；在度量名词前，表示付工资、卖、租等方式时，用the, 如paid by the hour (day, moth, piece…), sold by the yard (dozen, ton…)，比较by weight (按重量)。