题干
—Why don't you go out to play, Rose?
—I'm afraid I can't. I have much homework ________.
A：do
B：does
C：doing
D：to do
答案(点此获取答案解析）
D
—Why don't you go out to play, Rose?
—I'm afraid I can't. I have much homework ________.
A：do
B：does
C：doing
D：to do
，若函数y=f（x）﹣c的图象与x轴恰有两个公共点，则实数c的取值集合是（ ）