函数y=f(x)在区间(a,b)(a<b)内有零点,则[ ]
A.f(a)f(b)<0
B.f(a)f(b)=0
C.f(a)f(b)>0
D.f(a)f(b)的符号不定
答案:D
The last train left, so I ______ stay here until tomorrow. [ ]
A. must
B. have to
C. stop
D. live
阴虚毒恋型肛周脓肿偏脾虚者:()
A.青蒿鳖甲汤和三妙丸加麦冬、沙参、马兜铃
B.青蒿鳖甲汤和三妙丸加白术、山药、扁豆
C.青蒿鳖甲汤和三妙丸加龟版、玄参,生地改熟地
D.六味地黄丸
E.补肺汤