下面句中有一处错误，请找出来并改正。

I have a e-dog.It is lovely.I like it very much.

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如图是研究“滑动摩擦力”的实验．

观察下列等式： $\frac{1}{1\times 2}=1-\frac{1}{2}$ ， $\frac{1}{2\times 3}=\frac{1}{2}-\frac{1}{3}$ ， $\frac{1}{3\times 4}=\frac{1}{3}-\frac{1}{4}$ ，

将以上三个等式两边分别相加得： $\frac{1}{1\times 2}+\frac{1}{2\times 3}+\frac{1}{3\times 4}$ =1﹣ $\frac{1}{2}+\frac{1}{2}-\frac{1}{3}-\frac{1}{4}$ =1﹣ $\frac{1}{4}$ = $\frac{3}{4}$ ．

根据对话内容和汉语提示，用适当的表达完成对话。

A: Where is Jim? He isn't at school today.

B: I ____ (认为他不能) come to school today.

A: Why not?

B: He has to ____ (呆在家) and look after his mother.

A: ____ (怎么了) with his mother?

B: She ____ (得了重感冒) yesterday.

A: I'm sorry to hear that. Did she ____ (看医生)?

B: Yes. The doctor said she had to lie down and rest ____ (几天).

A: I hope she ____ (快点儿好起来). Then are you free after school?

B: Yes. Why? 

A: Let's go to see him and take the homework to him.

B: That's a good idea.