The hero’s sacrifices for the county were never officially ______, which made all of us feel discouraged.

下列各项中，加线词语使用恰当的一项是（     ）

Some pre-school children go to a day care center,____ they learn simple games and songs.

There are ______ people ,so it’s very crowded .

She is not a student. — He is not a student,______.