下列各句中，没有语病的一句是

What color is it—It’s ______.

With the word “PM25” ____ appearing in media reports, people pay greater attention to it and seek health tips for smoggy days

Could you tell me how long do you _________ on your homework every day

Did you receive the letter the next day?— NoSomehow, it was three weeks ______ I received it.[ ]