What colour is it? It's... — 英语选择题

颜色卡上写着：the ruler—blue；the pencil—green；the book—red。选出询问铅笔颜色且答语正确的一项。A. —What colour is it? —It's blue. B. —What colour is the pencil? —It's green. C. —What colour is the book? —It's green. D. —What colour is the pencil? —It's red.