—Thisisausefuldictionary,Ithink.—Soitis,andit’s

问题详情：

 —This is a useful dictionary, I think. —So it is, and it’s ______ unusual one.

       A. the                  B. an                        C. a                      D. 不填

【回答】

B

知识点：冠词

题型：选择题