题干
Research shows that people feel unhappy and worried when they have nothing to do.________，the happiest are those who are busy.
A：In short
B：In fact
C：As a result
D：For one thing
答案(点此获取答案解析）
B
装入带活塞的密闭容器中，当反应
达到平衡后，慢慢压缩，下列叙述正确的是