According to the behaviorist view of language acquisition，（）and（）are preliminary or fundamental， and discrimination and generalization are crucial or key to language development.

According to the behaviorist view of language acquisition，（）and（）are preliminary or fundamental， and discrimination and generalization are crucial or key to language development.
A.practice
B.imitation
C.pre-equipped UG
D.inner mechanism
正确答案：practice；imitation