信封是一种扁平的容纳物，用来送信的。

An envelope is a flat paper container used to send a letter.

youdao

他第一个创意是设计一种扁平而易于堆放在火车厢里的行李包。

His first invention was to design luggage that was flat and therefore easy to stack in railway carriages.

youdao

欢迎来到一分钟英语。信封是一种扁平的容纳物，用来送信的。

Welcome to English in a minute. An envelope is a flat paper container used to send a letter.

youdao

One of these classrooms in this building in another classrooms again is flat classrooms with thirteen tables and a lot of nice space between them.

这栋楼里的一间教室,是另外一种教室,有13张桌子的扁平型教室,之间还有足够的空间。

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