Weddingbee boards

I'm ashamed to ask this but I don't know what to write in a card for a couple of friends whose wedding gifts I'm giving deliquently. I went to three weddings this summer that were all out of town for me and since I'm planning my own wedding, money is tight. I'm just getting around to getting them gifts and I don't know what to write in their cards!

Do I just go with what I would have written in their card had I brought their gift with them? I don't know if I should explain the reason for the delay (they do all know that we're planning a wedding) or just leave it out any explanation/excuse? 

I appreciate any positive advice you have!