Complete the following sentence with a (compound) word derived f

Complete the following sentence with a (compound) word derived from the one(s) given in bracket.

His sudden （ ） kept him in Beijing for three months．(ill)

根据前文sudden形容词，可知空格处应该填名词，ill的名词形式为illness疾病。句意：他突然生病，在北京呆了三个月。