胚珠是半球形的，有2个被膜，腱鞘状，而原孢子细胞直接作为大孢子母细胞起作用。

The ovules are hemitropous, with 2 integuments, tenuinucellate and the archesporial cell functions directly as the mega-spore mother cell.

youdao

可以使用PRD球形和半球形的管道终端。

With PRD PEEM's both spherical and semi-spherical pipe ends are possible.

youdao

大致呈半球形的破坏区域，大小依核弹的当量、引爆深度和土壤质地而定。

The size of the roughly hemispherical destruction zone that results depends on the yield of the weapon, the detonation depth and the composition of the ground.

youdao

Timpani or as it's sometimes called a kettledrum, and it was playing two different pitches, actually sort of playing this pitch and this pitch, the octave and then the fifth.

定音鼓,或者有时称作半球形铜鼓,它正演奏两个不同的音高,实际上在演奏这个音高和另外一个音高,八度音阶和这个五度

耶鲁公开课 - 聆听音乐课程节选