这么难的听力，这么难的作文，雅思你是不是舍不得我想我们明年再见啊

听力 雅思考试 given 2024-12-28 15:04  2

We use differentiation to find thegradientof a graph at any given point – that’s the steepness of the graph.

数学 differentiation given 2024-12-06 09:47  3