Apples are usually sold by ________ weight and eggs are sometimes sold by ________ dozen.

A. the; the　　　　　　B. /;a               C. /; the　　　　　　　D. the; a

Apples are usually sold by ________ weight and eggs are sometimes sold by ________ dozen.

　　A. the; the　　B. /;a       C. /; the　　　D. the; a

 It’s incredible that you made ______ mistake alike for ______ third time. How can you be so forgetful?

A. a; a        　　　　B. a ; /              C.　the ; the           D.　the ; /

－They decide to take　 sail around the island.

　 －When will the ship set　 ____ sail?

A. a; /　 B. /; a

C. a; the　 D. the; /

Most animals have little connection with 　　　　 animals of 　　　　 different kind unless they kill them for food.?

A.the;a　　　　　 B./;a?

C.the;the　　　　 D./;the