n.高興；快活

Our friends have a look of cheerfulness. 我們的朋友看上去很高興。

Cheerfulness doesn't always imply happiness. 快活并不總是意味著幸福。

In your latest books, the sense of menace has receded, and the prevailing atmosphere is one of quasi mathematical, geometric cheerfulness. 在你最近出版的書中，危機感有所減退，但是占主要地位的是一種類似數(shù)學(xué)的，幾何學(xué)的快活。