问题补充:
--- What’s this?
--- It’s .
A. an ID card
B. a orange
C. ruler
D. an UFO
答案:
(答案→)A. an ID card
B. a orange
C. ruler
D. an UFO
解析:A. an ID card I的发音是[ai]元音,故用an; B. a orange [??]元音开头,故用an,错误。
C. ruler 可数单数名词不能单独用,要在前面加a; D. an UFO [ju: ef ??]第一个发音是辅音,所以用 a,选项错误。故选A