1、Answer - the focus is on the understandability of basic concepts, not on performance.
答-重點是基本概念易懂，而不是性能。

2、The understandability of teaching is an important standard for measuring the teaching level.
教師的教學是否具有可懂性是衡量教師教學水平的重要標準之一。

3、The four principal qc are relevance reliability understandability and comparability.
四個主要的特性是中肯，可信，易懂和可比性。

understandability翻譯