There are three main types of descriptive methods: observational methods, case-study methods and survey methods.

描述性研究法一共分为三类：观察法，案例分析法以及调研法。

youdao

There are three main types of descriptive methods: observational methods, case-study methods and survey methods.

描述性研究法一共分为三类：观察法，案例分析法以及调研法。

youdao