题目

—What ____ news!—Yes, all of the children were ____.A. excited; exciting    B. exciting; excited     C. excited; excited 答案：B解析:略设α=arctan(),β=arctan(),γ=arctan(-π),则(    )A?α＜β＜γ                                B?α＞β＞γC?β＜α＜γ                                D?β＞α＞γ