In France, it's _____ to say you are full. [ ]
A. polite
B. nice
C. kind
D. rude
答案:D
对于抛物线C:y2=4x,我们称满足y02<4x0的点在抛物线的内部,若点M(x0,yo)在C的内部,则直线l:y0y=2(x+x0)与抛物线C有______个公共点.
非水碱量法最常使用的试剂有
A.冰醋酸
B.高氯酸
C.结晶紫
D.甲醇钠
E.醋酸汞