表中 $u_i=\frac{1}{x_i}$ ， $\overline{u}=\frac{1}{8}\sum _{i=1}^8{u}_i$ .

（附：对于一组数据 $\left({\omega }_1,v_1\right),\left({\omega }_2,v_2\right),\cdots ,\left({\omega }_n,v_n\right)$ ，其回归直线 $\widehat{v}=\widehat{\alpha }+\widehat{\beta }\omega$ 的斜率和截距的最小二乘估计分别为 $\beta =\frac{{\sum }_{i=1}^n\left({\omega }_i-\overline{\omega }\right)\left(v_i-\overline{v}\right)}{{\sum }_{i=1}^n{\left({\omega }_i-\overline{\omega }\right)}^2}$ ， $\widehat{\alpha }=\widehat{v}-\widehat{\beta }\omega$ ）

增加：在缺词处加一个漏字符号（∧），并在其下面写出该加的词。

删除：把多余的词用斜线（\）划掉。

修改：在错的词下划一横线，并在该词下面写出修改后的词。

注意：1).每处错误及其修改均仅限一词；

2).只允许修改10处，多者（从第11处起）不计分。

    My grandfather and I enjoy fishing.

    One Sunday morning we go fishing at a lake. We took ours fishing poles and headed for the lake. As soon as we arrived, so we dropped the lines into the water. Before waiting for about half an hour, I was beginning to get impatiently. I wanted to give up, and my grandfather told me to wait a little longer. Finally, there were a sudden pull at the pole and fish was caught. Within the next few minute, my grandfather also caught a fish.

    Felt hungry, we built a fire by the lake and barbecued the fish. It was delicious.

北京是全国的（    ）