yingbonnie wrote:1. Their excrement smelled so bad.
2. Their excrement were very stinky.
Could I say that they have the same meaning?
Yes, same meaning.
But, as far as I know, excrement
, so 2 should be:
Their excrement was
is informal. Though possible, it is a strange combination with the formal word excrement
. More formally, you could use the verb to stink
Their excrement stank.