This is ID card and that is book. A. a an B. an; an C. an; a

问题补充：

This is ID card and that is book.

A. a, an B. an; an C. an; a

答案：

解析：考查冠词的用法。ID card中的字母I发音是元音，故用不定冠词an，排除A；book的首字母发音是辅音，故用a，排除B。故选C。