最基本的历史资料的初次整理的历史指的是下列哪类历史资料：（）
A、编年史
B、纪传史
C、区域史
D、断代史
参考答案：A
f(x)是定义在（-∞,+∞）上的偶函数，且x≥0时，f(x)=x3+x2,则当x＜0时，f(x)="_______."
___ into use in April 2000, the hotline was meant for residents reporting water and heating supply
breakdowns. [ ]
A. Put
B. Putting
C. Having put
D. Being put
