The world has about 3000 languages， which can be grouped into roughly 300 language families on the basis ofsimilarities in their basic word stock and（）.

The world has about 3000 languages， which can be grouped into roughly 300 language families on the basis ofsimilarities in their basic word stock and（）.
A、grammar
B、construction
C、pronunciation
D、notion
正确答案：A