in a way that is always calm and controlled, even in difficult situations that would cause other people to worry or get angry

In his imperturbably polite way, he ignored his opponent’s taunts. 他沉着而礼貌地忽视了对手的嘲讽。

The inhabitants of the area imperturbably got on with their lives. 这个地区的居民不慌不忙地继续着他们的生活。