So we've been chewing over the Autumn Statement for a couple of weeks now.

所以我们已经仔细研究了秋季声明几个星期了。

Tell him you've been chewing things over – it means you've been thinking about your proposals and say I have come to a final decision.

告诉他，你已经仔细考虑过了。意思就是说，你已经考虑了他的求婚，并要得出一个最终的结论。