By contrast , the process for goethite and manganite were exothermic.是什么意思？

By contrast , the process for goethite and manganite were exothermic.

硼在针铁矿、水锰矿上的吸附为放热过程,解吸为吸热过程.

by

prep. 在…旁边，表示方式，由于，经过；adv. 经过，表示保留或保存时用，短暂拜访；

例句
...expensive make-up that we saw being advertised by a beautiful model...
我们所见的由一位漂亮模特代言的昂贵化妆品

contrast

n. 对比，对照，差异，对照物，对立面，[摄]反差；

例句
There is also an artful contrast of shapes...
形状的对比也很巧妙。

the

art. 指已提到的人（物），指说话人与听者已知的人（物），用于独一无二的事物前，与形容词最高级和序数词连用；

例句
He did have a real knowledge of the country...
他对该国的确知之甚多。

process

n. 过程，工序，做事方法，工艺流程；vt. 加工，处理，审阅，审核；vi. 列队行进；

例句
Once you have registered your particulars with an agency and it has banked your cheque, the process begins.
一旦在某个代理行登记了详细信息并由它将支票存入银行，这一程序就开始了。

for

prep. 为，为了，倾向于，关于，当作；conj. 因为，由于；

例句
I've come looking for a bit of advice.
我特来讨教。

goethite

n. 针铁矿；

例句
The absorption reactions of goethite and its precursors on arsenite were studied.
观察了针铁矿及其前体对溶液中亚砷酸根离子的吸附过程和吸附性能.

and

conj. 和，与，而且，于是，然后，因此；

例句
I spend a lot on expensive jewelry and clothing...
我花很多钱购买昂贵的首饰和衣服。

manganite

n. 水锰矿，亚锰酸盐；

例句
By contrast , the process for goethite and manganite were exothermic.
硼在针铁矿、水锰矿上的吸附为放热过程,解吸为吸热过程.

were

be的过去时复数和第二人称单数形式，有时代替 was,用于条件从句、动词 wish 之后等；

例句
Shops, houses, and vehicles were set ablaze.
店铺、房子和车辆全都陷于火海。

exothermic

adj. 发热的，放出热量的；

例句
Is Hell exothermic ( gives off heat ) or endothermic ( absorbs heat )?
地狱是散 发热量 还是吸收热量?