Hydrogen sulfide is the gas that gives rotten eggs and sewage their distinctive smell.
(Hydrogen sulfide; is; the gas that gives rotten eggs and sewage their distinctive smell) (the gas; gives; rotten eggs) (the gas; sewage; their distinctive smell)
Hydrogen sulfide the gas the gas
is gives sewage
the gas that gives rotten eggs and sewage their distinctive smell
rotten eggs
their distinctive smell