疑难病症

xǔ duō yí nán bìng zhèng yào hào shí xǔ duō nián cái néng gǎo míng bai

许多疑难病症要耗时许多年才能搞明白。

It took years to understand many perplexing diseases.

shí bié yí nán bìng zhèng

识别疑难病症

distinguish difficult and complicated cases of illness