下列哪一项具有促进细菌附着至牙面及细菌间选择性黏附的功能（）。
A.水溶性葡聚糖
B.杂多糖
C.果聚糖
D.肽聚糖
E.胞内糖原
参考答案：A
As we all know, independence is very ________ for youngsters because sooner or later they will leave their families and live alone.
A．essential
B．accurate
C．flexible
D．temporary
人的血压分收缩压和舒张压(俗称“高压”和“低压”)，某人在某一时刻的舒张压为80 mmHg．合______ Pa，一个标准大气压的值约为此人舒张压的______ 倍．
