Where is Miss Smith A: On Thursday. B: Today. C: Tile day after tomorrow.

函数$f(x)=x+\sin x$的( )。 A: 上凸区间为$(2n\text{ }\!\!\pi\!\!\text{ },(2n+1)\text{ }\!\!\pi\!\!\text{ })$,下凸区间为$((2n-1)\text{ }\!\!\pi\!\!\text{ },2n\text{ }\!\!\pi\!\!\text{ })$ B: 上凸区间为$((2n-1)\text{ }\!\!\pi\!\!\text{ },2n\text{ }\!\!\pi\!\!\text{ })$,下凸区间为$(2n\text{ }\!\!\pi\!\!\text{ },(2n+1)\text{ }\!\!\pi\!\!\text{ })$ C: 上凸区间为$(n\text{ }\!\!\pi\!\!\text{ },(n+1)\text{ }\!\!\pi\!\!\text{ })$,下凸区间为$((n-1)\text{ }\!\!\pi\!\!\text{ },n\text{ }\!\!\pi\!\!\text{ })$ D: 上凸区间为$((n-1)\text{ }\!\!\pi\!\!\text{ },n\text{ }\!\!\pi\!\!\text{ })$,下凸区间为$(n\text{ }\!\!\pi\!\!\text{ },(n+1)\text{ }\!\!\pi\!\!\text{ })$

The text can be classified into three types: ______, ______ and ______. A: informative text B: functional text C: expressive text D: operative text

对数螺线$r={{\text{e}}^{\theta }}$在$\theta =\frac{\text{ }\!\!\pi\!\!\text{ }}{2}$对应点处的切线的直角坐标方程为( )。 A: $y+x={{\text{e}}^{\frac{\text{ }\!\!\pi\!\!\text{ }}{2}}}$ B: $y-x={{\text{e}}^{\frac{\text{ }\!\!\pi\!\!\text{ }}{2}}}$ C: $y={{\text{e}}^{\frac{\text{ }\!\!\pi\!\!\text{ }}{2}}}(x+1)$ D: $y={{\text{e}}^{\frac{\text{ }\!\!\pi\!\!\text{ }}{2}}}(x-1)$

Which of the following is not a basic procedure for text mining? A: Text preprocessing B: Text classification C: Text transformation D: Text mining