下列那种盐的水溶液显酸性。（）
A.弱酸强碱盐
B.强酸弱碱盐
C.弱碱弱酸盐的Ka＝Kb
D.弱碱弱酸盐的Kab
参考答案：B
—How many _____ teachers are there in your school?
— _____ them _____ over two hundred. [ ]
A. woman; The number of; is
B. women; The number of; is
C. woman; A number of; is
D. women; A number of; are
多普勒超声检测周围血管血流时，超声入射角通常要求使之
A．小于90°B．大于90°C．等于90°D．小于60°E．小于15°
