他得了很严重的疾病英语翻译为：he had a very serious illness。
他的 his
病 illness；sickness；disease
很 very；quite；awfully
严重 serious; grave; grievous
他的病很轻 his illness is not at all serious. not important
这种患者的病情必然是很严重的 he is too careful not to have noticed it
生气,后果很严重 angry
据说他受伤很严重 it was said that he was seriously wounded
问题已经很严重了 problem is already particularly acute
性质很严重的问题 a matter of a very serious nature
一个很严重的问题 a very serious problem
其他例子：
1、He was seriously ill .
他得了重病。
2、There was a very rich man who had plenty of property . one day , he suddenly fell seriously ill and couldnt recover
有一个人非常有钱，有很多财产，有一天，他得了重病，没办法康复。
3、The next morning he could not see or hear ; the jailer feared he was dangerously ill . edmond hoped he was dying . thus the day passed away
第二天早晨，他的视觉和听觉失去了作用狱卒以为他得了重病，爱德蒙则只想早点死去。