Every aspect of language is extremely complex. Yet very young (1) c________—before the age of five—already (2) k________ most of the intricate system we have been calling the grammar of a (3) l________. Before they can add 2+2, children are conjoining sentences, asking (4) q________, using appropriate pronouns, negating sentences, forming relative clauses, and using the syntactic, phonological, morphological, and semantic (5) r________ of the grammar.
A normal human being can go (6) t________ life without learning to read or (7) w________. Millions of people in the world today do. These same people (8) s________ and understand a language, and they can (9) d________ ideas as complex and abstract (10) a________ literate speakers can. Learning to speak and understand a language, and (11) l________ to read and write, are different. Similarly, millions (12) h________ never learn algebra or chemistry or how to (13) u________ a computer. They must be taught these skills or systems, but they do not have to be (14) t________ to walk or to talk. In fact, “We are designed to walk…. That we are taught to walk is impossible. And pretty much the (15) s________ is true of language. (16) N________ is taught language. In fact you can’t prevent the child (17) f________ learning it.”
The (18) s________ of the grammars of human languages has revealed a great deal (19) a________ language acquisition, about what a child does and does not do when learning a language. First, it is obvious that children do not (20) l________ a language (21) b________ storing all the words and all the (22) s________in some giant mental dictionary. The list of (23) w________ is finite, but no dictionary can hold all the sentences, which are (24) i________ in number. Rather, they learn to construct and understand sentences, most of which they have never produced or (25) h________ before.
Children must therefore (26) c________ the rules that permit them to use their language creatively. No one teaches (27) t________ these rules. Their parents are no (28) m________ aware of the phonological, morphological, syntactic, and semantic rules that are the children. Children seem to (29) act l________ efficient linguists equipped with a perfect theory of language, and they use this (30) t________ to construct the grammar of the language they hear.
children
（句意：五岁以前的孩子已经知道了语法中大部分难懂复杂的部分。由“young”和“before five”可知答案。）
know
language
（grammar语法，只能是语言的。）
questions
（句意：儿童可以连缀句子，问问题，用代词等。）
rules
（此处由本文最后一段第三行的“semantic rules”可知答案。）
through
（句意：一个普通人完全可以不会读，不会写而度过一生。go through life度过一生。）
write
（read和write并列，会读会写。）
speak
（句意：现在的人们说一种语言，并且理解这种语言。）
develop
（句意：与会读会写的人相比，不会读写的人同样可以产生复杂且抽象的想法。）
as
（as...as...，参考上题句意。）
learn
（句意：学习说话和学习读写是不一样的。由“learning to speak”可联想答案。）
humans
（句意：同样地，千千万万的人也从没有学过代数，化学和使用电脑。这里和millions of people对应，可知 此处还是人类。）
use
taught
（句意：他们一定需要别人教，才会掌握这些技能，但走路和说话却不用被教。“must be taught these skills”和“not have to be taught”形成对比。）
same
（句意：同样的情况也适用于语言学习。the same is true of...对……来说情况也是如此。）
Nobody
（句意：没有谁的语言时被教会的。）
from
（句意：没人能阻止儿童学说话。prevent sb. from doing sth.阻止某人干某事。）
study
（关于人类语言语法的研究揭示了人类习得语言的知识。reveal揭示，可联想到语言的研究成果。）
about
（句意：研究揭示了人类语言习得的知识，还有儿童在学习语言过程中做什么，不做什么等知识。空格所在的句子与后句并列，由后句的about可知答案。）
learn
（由上句的“learning language”可推测答案。）
by
（句意：儿童学习语言不是通过将所有的词汇和句子储存起来。）
sentences
（由下文的“but no dictionary can hold all the sentences”，可知words和sentences并列。）
words
（句意：字典可以装下所有的单词，但是装不下所有的句子。由上文words和sentences并列，可知此处缺少 words。）
infinite
（单词的数量是有限的finite，而句子的数量是无限的infinite。）
heard
（句意：儿童自己建构和理解句子，而这些句子他们之前从未用过的，或者从未听说过。）
create
（句意：孩子必须自己创造规则，这样他们才可以创造性地使用语言。由句末的creatively可知答案。）
them
（句意：没有人教他们这些规则，此处them代指孩子。）
more
（句意：父母并没有比孩子更多地意识到音系，词法，句法和语义的相关规则。be aware of意识到。）
like
（句意：孩子的行为就像掌握专业知识理论的语言学家一样。act like sb.像某人一样行事。）
theory
（句意：孩子按照这种理论建构自己听到的语言的语法。前面一句出现perfect theory，空格前的this就指代这种理论。）