Around（ ）_ months, the child begins to learn words at a rate of one every two waking hours, and keeps leaning that rate or faster through adolescence.
A.4 B.6 C.10 D.18正确答案D
Around（ ）_ months, the child begins to learn words at a rate of one every two waking hours, and keeps leaning that rate or faster through adolescence.
A.4 B.6 C.10 D.18正确答案D
