圆底的

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

边缘是平坦的，有一个相当深的底部，圆底。

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

本文介绍一种用三颈圆底烧瓶作蒸汽发生的半微量水汽蒸馏装置。