The old lady has developed a _______ cough which cannot be cured completely in a short time.
perpetual
permanent
chronic
sustained
本题考查形容词辨析
C选项,句意为“这个老妇人患了慢性咳嗽,短期不可能痊愈”,chronic“长期的,慢性的”。chronic disease专指“慢性病”,综上,C选项正确。
A选项,perpetual“永远的,永恒的”,故排除。
B选项,permanent“永久的,持久的”,故排除。
D选项,sustained“持续的”,故排除。
故正确答案为C项。