8. 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

 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

15. 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

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

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