系统软件和应用软件的相互关系是( )。
A．前者以后者为基础
B．后者以前者为基础
C．相互没有关系
D．相互支持
参考答案：B
Jane's always nervous when she has to make a speech; she must accustom herself to be __ when she
is with people. [ ]
A. at ease
B. in disguise
C. at risk
D. in relief
小儿急性腹泻的病程是
A．大于2周
B．小于2周
C．小于1个月
D．2周～个月
E．1～2个月
