—Be careful ! There is dog lying on the ground.—Thanks a lot.A. aB. anC. theD. /

问题补充：

—Be careful ! There is dog lying on the ground.

—Thanks a lot.

A. a

B. an

C. the

D. /

答案：

(答案→)A. a

B. an

C. the

D. /

解析：本空表示第一次提到的不特定物dog，故选用不定冠词， 又因dog是以辅音因素开头的单词。