adj.[生](细胞或微生物的培养)生活期有限的

动词span的过去式及过去分词形式.

A bridge spanned the stream. 一座桥横跨这条河流。

Emily is a Londoner born and bred and, for a woman some years past the allotted span, of a truly remarkable vigour and alertness. 埃米莉生在伦敦长在伦敦，虽已年逾古稀，但实在令人惊讶的是，她仍精力充沛，耳聪目明。

The river Thames is spanned by many bridges. 泰晤士河上有很多桥。

His life had almost completed its span. 他的生命几已到尽头。