-不明飞行物的英语缩略形式是______。 A. UFO B. BBC C. NBA
—______ Monday we have a basketball game. — Is it _______ the morning?
—Where are the books? —_______ in the bookcase. Do you need _______ now?
—Is the blue ruler _______? —No. _______ ruler is red.
This morning I have _______ art lesson. Art is _______ useful subject.
It is __________ difficult work __________ nobody can do it well.