She took it calmly at first but under the surface was seething.

她起初处之泰然，但内心却是怒火中烧。

She put a hand on her hip, grinning derisively, while I seethed with rage.

她把一只手放在腰上，嘲弄地咧嘴而笑，而此时我已怒火中烧。