Then explain why after leaning over in a chair for about four minutes last week it took me just as long to straighten up when I stood.
(Grammar question. Should that sentence end with a "period" or a "question mark"?)
Grammar answered: Are you asking me or are you making a statement?
Do you really want an answer? If yes then put a big fat question mark on the end.
When in doubt, get to the root of the sentence:
"Explain to me."
Now say, "Explain to me?" Sounds stupid, and it is wrong.
"Explain it to me" is a statement, not a question.
Go directly to school. Do not pass go. Do not collect $200.00.