Question

希望英语好的好心人给出参考答案，非常感谢!

Having no language, infants cannot be told what they need to learn. Yet by the age of three they will have mastered the basic structure of their native language and will be well ___1___ their way to communicative competence. Acquiring their language is a most ___2_____ intellectual feat. Studies of ____3_____ children learn language generally agree that the most remarkable aspect of this feat is the rapid acquisition of grammar. Nevertheless, the ability of children to conform ____4____ grammatical rules is only ____5_____ more wonderful than their ability to learn words. It has been estimated that the ____6_____ high school graduate in the United States has a reading vocabulary of 80,000 words, which includes ____7_____expressions and _____8______ names of people and places. This vocabulary must have been learned over a period of 16 years. From the figures, it can be calculated that the average child learns ____9____ a rate of about 13 new words per day. Clearly a learning process of great complexity goes on at a rapid ____10_____ in children.
1. A. in B. on C. under D. for
2. A. impressive B. expressive C. repressive D. persuasive
3. A. where B. when C. which D. how
4. A. to B. for C. with D. in
5. A. greatly B. slightly C. a lot D. a great deal
6. A. common B. ordinary C. average D. usual
7. A. idiomatic B. idiom C. idioms D. idiot
8. A. proper B. appropriate C. suitable D. improper
9. A. in B. on C. at D. for
10. A. time B. rate C. place D. way

Answer 1

Having no language,infants cannot be told what they need to learn.Yet by the age of three they will have mastered the basic structure of their language and will be well on their way to communicative competence. Acquiring their language is a most impressive intellectual feat.Studies of how children learn language generally agree that the most remarkable aspect of this feat is the rapid acquisition of gram- mar.Nevertheless, the ability of children to conform to grammatical rules is only slightly more wonderful than their ability to learn words.It has been reckoned that the average high school graduate in the United States has a reading vocabulary of 80,000 words,which includes idiomatic expressions and proper names of people and places.This vocabulary must have been learned over a period of 16 years. From the figures,it can be calculated that the average child learns at a rate of about 13 new words per day.Clearly a learning process of great complexity goes on at a rapid rate in children.
推理出主题句：It mainly talks about the methods,characteristics and procedures of language learning of children. 就很简单了
即；BADAB CAACB
这个我们以前做过，能保证正确。

Answer 2

ABDAB BABCB

自己做的，有不明白的，欢迎讨论

Answer 3

1~10 ABDABAAACB

Answer 4

1—5BADAB 6—10CAACB

Answer 5

B A D A B C A A C B