Then before we talk about a price, you'd better explain what I have to do.
Before we begin I had better explain something to you.
In case you did not, I had better explain who he is.
"I think perhaps you had better explain yourself," she said.
"I think you people had better explain," he said at last, looking up.
At this point I had better explain who "we" are.
It would also better explain why there is no mention of this story before the early 1900s.
You'd better explain this question because it's a little complicated.
It will explain his last days better than I can.
"I think you'd better explain the whole thing," he said.