()20. It's hard to believe such a difficult maths problem without the help of the teacher.

A.what you will manage to work out
B.how did you manage to work out
C.how you managed to work out
D.why did you manage to work out

20.C

【分析】本题考查宾语从句的语序与引导词选择。首先，believe后接宾语从句，宾语从句需用陈述语序，据此排除疑问语序的选项；其次，结合从句成分和句意判断合适的引导词，最终确定答案。
【解析】1. 宾语从句必须使用陈述语序，选项B、D为疑问语序（did提前），不符合要求，排除；2. 剩余选项A中，what在从句中需充当主语或宾语，但从句已有宾语“such a difficult maths problem”，无需what引导；3. 选项C中how引导宾语从句表方式，且为陈述语序，符合句意“很难相信你是如何在没老师帮助下做出这么难的数学题的”，因此选C。
【答案】C
【知识点】宾语从句（语序、引导词）
【点评】本题考查宾语从句的基础知识点，需掌握宾语从句用陈述语序的规则，同时结合句意和从句成分选择正确引导词，是初中英语常考题型，难度适中。
【难度系数】0.6

(A)
根据句意及汉语提示填空。
1. The beauty of Taizhou is so amazing that words cannot (描述)it.
2. The Spring Festival usually comes in (一月)or February, people in China get to - gether to celebrate it.
3. — Next month, I'll take a (直接的)flight to Guilin.
— Really? Have a pleasant trip!
4. In order to protect our national (产品), the Chinese government has taken action to control overseas purchasing(海外代购).
5. The (花费)of the trip to Shanghai Disneyland Park is about 800 *yuan* per person.
6. The father took a pair of (剪刀)and cut her hair.
7. You'll find differences between two (文化).
8. I saw the White House where the (总统)of the USA lives.
9. Watching English movies has become one of the (活动)we enjoy most in our Eng - lish classes.
10. The (架子)in the library are full of different kinds of books.
11. The Smiths will travel (在国外)to spend their summer holiday.
12. Two big hamburgers were (吃)within two minutes by Eddie.
13. When I arrived, I found her in a (谈话)with Mr Li.
14. I think (两者都不)of you is right.
15. It's nothing (严重的).
16. You can fly (直接地)to Shanghai from most British airports.
17. Recently car engineers have (成功)in creating a new kind of car that runs on gasoline and electricity.
18. She has a good (教育), and she goes to work even after getting married.

1. describe 2. January 3. direct 4. products 5. cost 6. scissors 7. cultures
8. president 9. activities 10. shelves 11. abroad 12. eaten 13. conversation
14. neither 15. serious 16. direct 17. succeeded 18. education

【分析】
本题为根据句意及汉语提示填空的词汇题，解题思路为：先根据括号内的汉语提示确定所需单词的词义，再结合句子的语法结构（如情态动词后接动词原形、名词单复数、被动语态的过去分词、固定搭配等），判断单词的正确形式，最终填入符合语境和语法的单词。
【解析】
1. 情态动词can后需接动词原形，汉语提示“描述”对应的动词为describe，故填describe。
2. 表示月份的名词“一月”为专有名词，首字母大写，对应January，故填January。
3. 此处需用形容词修饰名词flight，汉语提示“直接的”对应的形容词为direct，故填direct。
4. 句意表达“民族产品”，产品为可数名词，此处泛指各类产品，需用复数形式products，故填products。
5. 此处需用名词表示“花费（费用）”，对应cost，故填cost。
6. “剪刀”常用复数形式scissors，故填scissors。
7. 数词two后需接可数名词复数，“文化”对应的复数形式为cultures，故填cultures。
8. 此处特指美国的总统，用单数名词president，故填president。
9. “one of + 可数名词复数”表示“……之一”，“活动”对应的复数形式为activities，故填activities。
10. 句中be动词为are，主语需为复数，“架子”对应的复数形式为shelves，故填shelves。
11. 此处需用副词修饰动词travel，“在国外”对应的副词为abroad，故填abroad。
12. 句子为被动语态，结构为“be + 过去分词”，“吃”的过去分词为eaten，故填eaten。
13. 固定搭配“in a conversation”表示“在谈话中”，对应汉语提示“谈话”，故填conversation。
14. “两者都不”对应的不定代词为neither，作主语时谓语用单数，符合句意，故填neither。
15. 此处需用形容词修饰不定代词nothing，“严重的”对应的形容词为serious，故填serious。
16. 此处direct可作副词修饰动词fly，意为“直接地”，符合用法，故填direct。
17. 句子为现在完成时，结构为“have + 过去分词”，“成功”的过去分词为succeeded，故填succeeded。
18. 形容词good后需接名词，“教育”对应的名词为education，故填education。
【答案】
1. describe 2. January 3. direct 4. products 5. cost 6. scissors 7. cultures 8. president 9. activities 10. shelves 11. abroad 12. eaten 13. conversation 14. neither 15. serious 16. direct 17. succeeded 18. education
【知识点】
单词正确形式填空；词性辨析；时态语态
【点评】
本题考查基础词汇的运用，涵盖名词单复数、动词形式变化、词性转换、固定搭配等知识点，是初中英语常见的基础题型，侧重考查学生对核心词汇的掌握及在语境中灵活运用的能力，整体难度适中。
【难度系数】
0.6