The rim is flat and there is a rather deep well, or cavetto.

边缘是平坦，有一个相当部，或称为。

This paper introduces a simple semimicro-distillation apparatus,In this apparstus,a three-necked flask is used as steam generator.

文介绍一种用烧瓶作为蒸汽发生器半微量水汽蒸馏装置。