下列词语中字音全都正确的一组是（ ）

Today, we’ll discuss a number of cases ____ parents have much difficulty in communicatingwith their children[ ]

—I am going to Spain fort a holiday soon.   — ______.

Compared with that article, this article is but not _.

.The other day I was showing the boys theweekly chemistry experiment when, ________ I knew it, the mixture was bubblingover everywhere.