The sentence translates to: "He has been in Beijing for a year, his Chinese speaking is ( ) good."
This sentence requires an adverb to modify 'good'. Common adverbs that intensify 'good' in this context include 'very', 'quite', 'really', etc. Looking at the initial options provided (A: very, B: meaning, C: from, D: to give, E: expensive, F: outside), the word 'very' (fēicháng) fits perfectly here.
Therefore, the completed sentence is: 他来北京一年了,他的汉语说得非常好。
Answer: A