(2) 质点到达$x$坐标最大值时刻的速度和位置. A: $\vec{v}=-5t\hat{y},\vec{r}=12.5(\hat{x}+\hat{y})$ B: $\vec{v}=-5t\hat{y},\vec{r}=14.5(\hat{x}-\hat{y})$ C: $\vec{v}=5t\hat{y},\vec{r}=12.5(\hat{x}-\hat{y})$ D: $\vec{v}=-5t\hat{y},\vec{r}=12.5(\hat{x}-\hat{y})$

What does the man think of the hat A: This hat is very beautiful. B: This hat is not so beautiful. C: This hat is beautiful except the color.

请问 Is~it a~hat or a cat?这句话,_______ 单词不可以连读.（ ） A: Is and it B: it and a C: hat and or D: a and hat

均方误差是衡量贝叶斯估计的性能指标之一，若\(\hat A\)是基于观测量\(z\)对\(A\)的贝叶斯估计，则\(Mse(\hat A)\)的表达式是 A: （A）\(Mse(\hat A) = E\left[ {{{(A - \hat A)}^2}} \right] = \int_{ - \infty }^\infty {{{(A - \hat A)}^2}p(z;A)dz} \)； B: （B）\(Mse(\hat A) = E\left[ {{{(A - \hat A)}^2}} \right] = \int_{ - \infty }^\infty {{{(A - \hat A)}^2}p(A)dA} \) C: （C）\(Mse(\hat A) = E\left[ {{{(A - \hat A)}^2}} \right] = \int_{ - \infty }^\infty {\int_{ - \infty }^\infty {{{(A - \hat A)}^2}p} } (z,A)dzdA\) D: （D）\(Mse(\hat A) = E\left[ {{{(A - \hat A)}^2}} \right] = \int_{ - \infty }^\infty {\int_{ - \infty }^\infty {{{(A - \hat A)}^2}p} } (A{\rm{|}}z)dzdA\)

A hat stand is something that you can put your hat and clothes on.

(2)从$0$到$2s$内质点的位移; A: $-12\hat{x}m$ B: $21\hat{x}m$ C: $16\hat{x}m$ D: $12\hat{x}m$

What do they think of the hat A: The man thinks the hat fit well with the shoes, and he likes it. B: Although the hat is old fashioned, the woman likes it very much. C: The woman thinks the hat is fashionable but the man is out of fashion. D: The man doesn’ t like the hat because it was not nice with the shoes.

________hat is this? It’s________.

soft hat ______

RPM是Red Hat Package Manager（Red Hat软件包管理工具）的缩写。