1.The dog is a useful animal.

~ a 是指某一种（类，个等）， the 则是特指。
第一句话里 dog 指的是这个种类，要用the 表示，后面用a 是表示狗是一种动物，只是其中的一种，有用的动物还有其他的，所以不能用the。
第二句话里，这里并不知道是哪所大学，不确定，所以要用a , 后面的 a famous one ,也只是说它是一个出名的大学，言外之意就是还有其他出名的大学，这里的one 是代词，指代的是university。

1、The dog 指狗这种动物而非一只狗， a useful animal意思为一种有用的动物
2、a university 意思为一所大学，one指university

第一句的A指一种，而非特定的某种。
第二句也是指一所大学，而非特定的某一所大学。
ONE指university

1.The dog is a useful animal.句中的the表种类、类别，表示“狗”这个类别。如果此句换成：A dog is a useful animal也是正确的。
第二句中的one代表university.

1某所大学是泛指啊
2one 指代university

one 可能指代之前的那个university第一句，a dog可以指代任何一条狗，但是the dog专门指代那一条狗，不懂的继续问哦！

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芝罘区19362813445： the dog is 可以写成 the dog's 吗 - ？
丛叶采乐： 只是常见的缩写罢了, is可以缩写成's,而且's未必都是所有格.比方说He's got a lighter. 's是has.而且缩写不是很常见么像 I'm Lovin' It = I'm loving it.Beat 'em up = Beat them up.

芝罘区19362813445： 关于介绍小狗嗅觉的英文作文 - ？
丛叶采乐： Dogs belong to the canine. When a dog follows its nose, it's actually being led by thee key senses. Sight:a glimpse of the enemy saves them barking up the wrong tree. Sound: a bark can be a fierce threat, but it's also how canines make their long ...

芝罘区19362813445： 根据短文内容及首字母提示完成短文 the dog is a real a - ？
丛叶采乐： Look at the picture. How interesting the dog is! Sam is a lovely dog. He is a real artist. His hobby was ___1painting__. The hobby not only makes him ___2_famous__, but also makes him rich. Sam has drawn 22 paintings. ___3All___ of them are ...

芝罘区19362813445： 写动物的英语作文,最好是狗. - ？
丛叶采乐： Dogs(狗) Dogs belong to the canine. When a dog follows its nose, it's actually being led by thee key senses. Sight:a glimpse of the enemy saves them barking up the wrong tree. Sound: a bark can be a fierce threat, but it's also how canines ...

芝罘区19362813445： 用英语写一篇关于狗的说明文(60个单词左右) - ？
丛叶采乐： When a dog follows its nose, it's actually being led by thee key senses. Sight:a glimpse of the enemy saves them barking up the wrong tree. Sound: a bark can be a fierce threat, but it's also how canines make their long distance calls. Smell: this tells ...

芝罘区19362813445： The dog is our friend.与A dog is our friend.这两个句子有什么区别 - ？
丛叶采乐： the dog 是特指某一只狗,比如说你自己养的一条狗或者某只特别忠诚、特别勇敢的狗,也许他陪伴过你甚至救过你,所以它是你的朋友 A dog 是泛指狗,也许你是一个动物爱好者 ,所以你想表达的意思是:狗是我们的朋友.

芝罘区19362813445： 1.That is my dog.(同义句) - ？
丛叶采乐： 1. That dog belongs to me. 或者,The dog is mine.2. Yes, they are.

芝罘区19362813445： 根据短文内容及首字母提示完成短文 the dog is a real atist - ？
丛叶采乐：[答案] Look at the picture.How interesting the dog is!Sam is a lovely dog.He is a real artist.His hobby was ___1painting__.The hobby not only makes him ___2_famous__,but also makes him rich.Sam has drawn 22 paintings.___3All___ of them are abstract....

芝罘区19362813445： 英语题目.改错题1、The dog is very lovely .Let's bring it to home.2、Who child is that girl? - ？
丛叶采乐： 1、The dog is very lovely .Let's bring it to【去掉 to】 home. 【home 是副词,前面不能加 介词】2、Who【改成 Whose】 child is that girl? 【那女孩是谁的孩子?】 One of the girls ___from England .a am b is c are d be 选 B 第三人称 单数

芝罘区19362813445： 将下列句子合并为含定语从句的复合句1.The dog is mine.The dog is black2.Here is the ball.You are looking for the ball3.Kate likes the movie.The movie is about... - ？
丛叶采乐：[答案] 1.The dog which is black is mine.2.Here is the ball which you are looking for.3.Kate likes the movie which is about music.4.The man who is standing on the playground is my Chinese teacher.或The man wh...