关于卢瑟福提出的原子结构的核式模型，下列说法中错误的是（   ）

短文改错

假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下作文。文中共有l0处语言错误，每句中最多有两处。每处错误仅涉及一个单词的增加、删除或修改。

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(从笫11处起)不计分。

    I'm Wang Hong, a international student of Beijing University. I have something to talk with you. During last year's winter holiday, I go shopping with my classmates. While we were walking on the street, we saw several beggar standing on the road and asking for money. Many of them were disabling, which made me feel very much sad. Among them were old people, young people and even children. I noticed some passers-by ignore them instead of given them money. When I wanted to help them, my classmates stopped us. They told me whether these beggars were not worth showing mercy to because most them cheated people. Should I helped them?

把下面句子变换一下说法，意思不变

老师，您正在休息，我们不惊动您。

如图，将三角形ABC沿BC方向平移acm得到三角形DEF，若△ABC的周长为bcm，则四边形ABFD的周长为____ cm（用含a，b的式子表示）