我不是韩国留学生。 (right) 这儿是他的班。(right, but we usually omit the words "儿",and directly say :这是他的班," ) 他是这儿的班.(right, but here 他 no more means a man, it means a class, so this sentence's meaning become : It's the class belong here. And "他" should be changed into "它" 他们都也汉语学生.( you can only use one word 都 or 也, and add the " 是" in the sentence. so there would be two sentences of different meaning. One is :他们都是汉语学生, here 他们 means the two person you mentioned before. Another is : 他们也是汉语学生,maybe there are more than 2 person and the rest are Han language learner too.)

我不是韩国留学生。 这儿是他的班。 他是这儿的班。（他是这个班的。） 他们都也汉语学生。（他们也都是中国学生。/他们也都是学习汉语的学生。）

you'd better give both the original sentences & translate sentences.

hello.Minjin, the first sentence "我不是韩国留学生。"is correct. the second one "这儿是他的班。", actually I can understand what you mean. You mean "This is his class." Is it right? In Chinese, we say"这儿是他（所在）的班级。" this will be better. the third one "他是这儿的班”, I think it should be like this"他是这儿的学生。" the 4th,"他们都也汉语学生。" it should be "他们也都是汉语学生。" "是" is a verb in Chinese,every sentence must have a verb,but there is no verb in your 4th sentence.

the first and second sentences are correct,but the rest are wrong. the third one "他是这儿的班" , "he"cant be a "class".“他”cant be “班"....i dont know if u catch me....if not, tell me and the forth.."他们都也汉语学生".."都"and"也" mean the same idea...u cant use both them at the same time.... if u still have questions ....ask me ...i will answer it again