Close one hand to form a ball.

VOA: special.2009.08.11

Notice the form of it, it's just the name of the class followed by open paren, close paren, treating it like a function.

我该怎么来使用类呢？,好，我可以像调用方法,一样调用类，你可以在下面看到，创建一个名为。

麻省理工公开课 - 计算机科学及编程导论课程节选

It's difficult to imagine that as an expression of genuine grief over the death of a genuinely close friend would take the form of a poem so learned, so filled with remote literary allusions and obscure opinions.

这首诗是为表达对挚友逝去的真挚悲痛,却采取了这样一种如此博学，如此充满,遥远的幻境和隐晦的观点的形式,这确实是难以想象的。

耶鲁公开课 - 弥尔顿课程节选