in home / house / class

Hello Vincet Teo:)!

I would say..

1.- Among the boys of the house, Ali is the fattest.
2.- Ali is that fattest boy of the home/the house/the class

..but, you'll have to wait for a native!

Vincent TeoCan I say,

(a) Among the boys / boy, Ali is the fattest in at home / homes.

(b) Ali is the fattest boys at home / in the house / in (the) class. (okay)

I am not really sure about my answer but that is my choice. Let's

Thanks for you all help. I will wait for the expert to answer my questions.

Vincent TeoCan I say,

(a) Among the boys / boy, Ali is the fattest in home / homes. This is not needed - Alternative sentence: "In the home OR At home, Ali is the fattest boy".

(b) Ali is the fattest boys boy at home / in the house / in (the) clas

Feebs, are the following sentences correct? Let's see my understanding of the prepositions:

1) I go to class everyday.
2) My friend is at class now.
3) My friend is in the class now.
4) I'm at home, please call my home number.
5) I'm in my home/I'm in the home
6)I'm in my parent's house/I'm in my parent's home

They all look fine to me.

Two minor points to make - if you use "the home" in the sentence "I'm in the home", it implies that you are in an orphanage or similar organisation [ The Home for Indigent Children]. We will generally use an identifier - my home, your home, my parents' home.
Also, parent's = one parent; parents' = both parents.

Thank you very much.

WesternAmericanFeebs, are the following sentences correct? Let's see my understanding of the prepositions:

1) I go to class everyday.

I go to class every day.

Have you forgotten? The word 'everyday' is an adjective: everyday duties, everyday life.

Feebs11They all look fine to me.

2) My friend is at class now. (Just to confirm: Is this sentence fine?)

.
I'd say it would be more typical to hear 'in class', but I wouldn't rule out 'at class'.
.
.