The correct sentence is:
"China has always fascinated me."
The word "China" is a singular noun, and we use the singular form of the verb "has" with singular subjects.
The sentence is in the present perfect tense, which requires the correct past participle form "fascinated", not "fascinates".
The correct sentence is "China has always fascinated me."
Among scientists, the discovery of the double helix structure of DNA and the genetic code it incorporates is widely regarded to be one of the most significant scientific discovery of the twentieth century.