Please correct my nepali

You are nice. Timi ramro chhau.
He is nice Oo ramro chha. 
THey are nice ooniharu ramra chhan.
I want to go to the store? what is this and these?
I want to buy something at the store
I want to take a shower
It has been raining here alot
I need to buy a boat
It has been raining here all day

Please correct my nepali

You are nice. Timi ramro chau.
He is nice O ramro cha
THey are nice tiniharu ramro cha
I want to go to the store? what is this and these? ma pasal ma jana chahanchu.yo k ho ra tyo k ho ?
I want to buy something at the store. ma pasal bata kehi kinna chahanchu.
I want to take a shower  ma nuhauna chahanchu.
It has been raining here alot .yaha dherai pani pareko cha.
I need to buy a boat. ma dunga kinna chahanchu.
It has been raining here all day. yaaha dinbhar pani pariraheko cha.

Please correct my Nepali

You are nice. >> Timi raamro chhau. 
He is nice. >>  U raamro chha. 
They are nice.  >> Uniharu raamra chhan. 
I want to go to the store. >> Ma storemaa (Pasalmaa) jaana chaahanchhu.  

what is this and these? >>  Yi ke hun ani ti ke hun ? 
I want to buy something at the store >> Ma storemaa kehichij kinna chaahanchhu. 
I want to take a shower >> Ma nuhaauna chaahanchhu. 
It has been raining here a lot. >>Yeha dherai paani pariraheko chha. 
I need to buy a boat >> Malai eauta dunga kinnu parchha. 
It has been raining here all day>> Yeha dinbhari paani pariraheko chha.