I wish I had a car.
돈이 많았으면 좋겠어요.
I wish I had a lot of money.
크리스마스에 눈이 왔으면 좋겠어요.
I hope it snows on Christmas.
-았/었으면 좋겠다 expresses a person’s wish or hope about something that has yet to be realized. It can also be used when expressing a desire for a situation to become the opposite of what it currently is. This expression corresponds to ‘hope/want’ in English. When the verb stem ends in ㅏ or ㅗ, then -았으면 좋겠다 is used; while -었으면 좋겠다 is used for all other verb stem endings. As for verbs ending in 하다, the form changes to -했으면 좋겠다.
In addition to -았/었으면 좋겠다，-았/었으면 하다 can also be used, but -았/었으면 좋겠다 indicates a stronger degree of hope or desire.
A: 몇 살에 결혼하고 싶어요? At what age do you want to get married?
B: 30살 전에 결혼했으면 좋겠어요. I’d like to get married before I’m 30.
A: 요즘도 바빠요? Are you still busy these days?
B: 네, 계속 바빠요. 좀 쉬었으면 좋겠어요.
Yes, I’m still busy. I wish I could have some time off.
A: 이번 방학에 뭐 할 거예요? What will you do this vacation?
B: 친구들하고 스키장에 갈 거예요. 방학이 빨리 왔으면 좋겠어요.
I plan to go skiing with my friends. I wish vacation would come sooner.
-(으)면 좋겠다 can be used in the same sense as -았/었으면 좋겠다, but because -았/었으면 좋겠다 supposes the realization of an as yet unrealized state, it more strongly emphasizes the verb.
• 돈이 많으면 좋겠어요. (The speaker is simply wishing to have a lot of money.)
• 돈이 많았으면 좋겠어요. (The speaker is supposing a situation in which he has a lot of money, which is in contrast to his current situation of having no money; thus the wish is emphasized.)