spent culture medium是什么意思

Spent medium:
the medium which is discarded because it has been depleted of nutrients, dehydrated,or accumulated toxic metabolic products after subculture.

Culture medium:
the broth that covers cells in the culture dish which contain nutrients to feed the cells as well as other growth factors that may be added to direct desired changes in the cells.

说简单点，Spent medium就是养过细胞的旧的培养基，Culture medium是刚加进去的新培养基

　　中文:用培养基

　　英语中spend的部分用法如下:

　　1. 在使用spend时,主语只能是表示人的名词或代词。例如:

　　Andy spent a lot of money on books. Andy花了很多钱买书。

　　2. 若表示"在......上花费(时间、金钱等)",常用句型spend some money/ some time on sth.,介词on后接名词或代词。例如:

　　Kitty spends two hours on her homework every day. Kitty每天花两个小时做家庭作业。

　　3. 若表示"花费(时间、金钱等)做某事",则常用句型spend some money / some time (in) doing sth.,此时第二个动词要用动词-ing形式,介词in可以省略。例如:

　　They spent 4450 yuan buying the big colour TV set. 他们买那台大彩电花了4450元。