「５」Ga can be put at the end of a sentence.
Note: These usages are similar to the examples for preliminary remarks, except the second clause isn't stated outright (Words in brackets show only one of various contexts)
a) Used to imply unstated meaning that contrasts "Well, yes, but...."
Ossharu koto wa mottomo desu ga....
What you say is quite right, but...[it's difficult to implement now].
b) Also used when wanting to soften the blow of a refusal: "I am sorry, but...."
Buchō wa ima kaigi-chū de gozaimasu ga...
The division chief is in a meeting now....[so you'll have to wait to see him].
「６」When ga is used at the end of a sentence or clause, and preceded by to ii, it indicates that the speaker wants the event to come out as said. Context is important with this, distinction: "It would be nice if; it would have been nice if."
Rainen gaikoku e ryokō dekiru to ii ga, dame no yō desu.
It would be nice if I could make a trip abroad next year, but it seems as though I can't [seems impossible].
Hayaku haru ga kuru to ii-n da ga.
It would be nice if spring came soon./I hope spring comes soon.
Kanojo ga dokushin da to ii-n da ga.
I hope she is single./(or knowing she is not) I wish she was single.
( ´•౪•`) こゆうきあいはら ( ´•౪•`)