英语翻译
问题描述：
英语翻译
In investigating the robustness of our results,we utilize a control variable(stock
of patents obtained in the past four years)that has been shown to be highly correlated with annual firm-level R&D expenses.
答
stock有对与某事物的一部分权力的意思,此处可以翻译为对与专利的使用权,stock of patents即专利权,robustness有强度的意思,此处可翻译为研究结果的可信度