教授简要描述了历史背景。

The professor provided a brief ___sketch of the historical context.

我已为您审阅准备了拟议项目的初步概要。

I have prepared a preliminary ___sketch of the proposed project for your review.

她的报告只是对复杂问题的简要描述，缺乏深入分析。

Her report was merely a ___sketch of the complex issue, lacking in-depth analysis.