uncheerfulness

n. 不高兴, 沉闷

例句与用法：

An unchecked flow of water; an unchecked temper.

顺畅的水流; 无拘无束的脾性

If this tendency goes unchecked, the situation will inevitably become more complicated.

这种倾向如果让它发展下去，情况将必然变得更加复杂。

A region despoiled of its scenic beauty by unchecked development.

由于不加限制的发展而使这个地区丧失了其美丽景色