他由于长期生病而瘦弱.用英语怎么说？

他由于长期生病而瘦弱.

He was emaciated by long illness.

he

pron. 他，它，一个人；n. 雄性动物；

例句
Logic had prevailed and he had abandoned the idea.
最终理智占了上风，他打消了那个念头。

was

v. 用来表示某人或某物即主语本身，用来表示某人或某物属于某一群体或有某种性质（ be的过去式 ），在，存在，不受干扰；

例句
There was a terrible sadness in her eyes...
她眼神中流露出深深的悲伤。

emaciated

adj. 瘦弱的，憔悴的；v. 使消瘦，使衰弱( emaciate的过去式和过去分词 )；

例句
...horrific television pictures of emaciated prisoners.
电视上骨瘦如柴的囚犯们的恐怖画面

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

long

adj. 长的，长时间的，冗长的，过长的，长音的；adv. 长久地，始终，遥远地；n. 长时间，长时期，[语]长音节，（服装的）长尺寸，长裤；vi. 渴望，极想；

例句
As long as most people are happy to have the monarchy, the abolitionist position is an arrogant fantasy.
只要大多数人还乐意保留君主制，废除它的主张就是痴人说梦。

illness

n. 疾病，某种具体疾病，不健康；

例句
Although his mental illness had coincided with his war service it had not been caused by it...
虽然他的精神病刚好在他参战期间发作，但并不是由此引起的。