come out of one's shell字面意思“从壳里出来”，表示“（使）变得不再自闭，（使）融入外部世界，不再羞怯，愿意与人攀谈，开始活跃起来，放开了一些”。

【例句】
Derek has really come out of his shell since he started working here.
自从开始在这儿工作以后，德里克真正变得不再自闭。

Her normally shy son had come out of his shell. He's more extroverted now.
她那平时害羞的儿子已经开始融入外部世界。他现在更加外向了。