@Caishen,
1.
Pueros et puellas in uia uideo
-->English: I see the boy and girl in the street.
Pueros and
puellas are plural, so "boys" and "girls".
2.
Cur discipulus libros magistri non legit?
-->English: Why does the teacher not read to the pupils?
Discipulus is nominative and therefore the subject of the sentence.
You omitted
libros, "books". It is accustive and the object of
legit.
Magistri is genitive, so "of the teacher" or "teacher's"
3.
Quamquam legatus captiuos liberat, uerba legati non laudatis.
-->English: Though/Although the officer released the prisoner,
you did not offer words of praise to the officer.
Capitiuos is plural, so "prisoners".
Non laudatis could be translated simply as "you did not praise".
I'd translate it as "you did not commend" in this context.
Uerba is the object of
laudatis, so "you did not commend the words".
Legati is genitive, so "of the officer" or "officer's".
4.
Carmina uirginibus et pueris canto.
English: Sing the songs of the maiden and the boy.
Uirginibus and
pueris are the plural dative, so "to the maidens and the
boys".
Canto is the first person singular, so "I sing".
I don't think it would be helpful for me to simply translate the rest.
Why don't you give them your best shot, post back here, and we can
go over them?
~George