堰前行近流速忽略不计时堰上总水头H0小于堰上水头H.
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Invariable wordss refer to those words such as since, when, seldom, hello, etc. They do not have inflective endings.
如果在制品的远浇口端有困气的现象，应该降低 注射速度（哪一级）
As for a syllable, nucleus is essential while ________ and coda are optional.
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