乳腺溢乳时首先应考虑（）
A.乳腺增生症
B.导管 * * 状瘤
C.纤维腺瘤
D.脂肪坏死
E.乳腺囊肿
参考答案：B
—What do you think we can do for our aged parents?
—You ____ do anything except to be with them and be yourself.
A．oughtn’t to
B．don’t have to
C．mustn’t
D．can’t
使不等式sin2x+acosx+a2≥1+cosx对一切x∈R恒成立的负数a的取值范围是______．
