Questions about example sentences with, and the definition and usage of "Awasmall"

A: × I think throwing awasmall garbage such as gum,plastic,bag,or tissue is a bad manner.
✓ I think littering small garbage such as bags, gum,plastic and tissues is bad manners.

× Not only when I see someone doing so,but also when I see garbage on ground,I feel disgusting.
✓ When I see someone doing this and when I see it on ground,I feel disgusting.

× their behavior do more hain than benefit for everyone.
✓ Their behavior does more harm than good for everyone.

× they are hunting a beautiful view of the city,people's feeling,and even creatures if they eat these garbage.
✓ They are hurting a beautiful part of the city,people's feeling,and even creatures if they eat the garbage.

× They probably don't take account of the others.
✓ They probably don't take account of other people

× So I feel uncomfortable with these acts.
✓ and so I feel disgusted by these acts.

I assume you mean throwing away trash on the floor and not in a trash bin the word for that is littering.
I also don’t know if you mean plastic bags or both plastic and bags

for example like plastic straws, plastic cups anything that is made of plastic etc
and paper bags, plastic bags etc

if you mean both plastic and bags maybe move the words so they aren’t next to each other
If you mean specifically bags that are made of plastic(plastic bags) then you don’t need the comma in the middle.