2． 介词填空

1)　　　　 Dave didn’t respond ______ any of her emails.

2)　　　　 He rested his elbows _______ the table and leaned forward.

3)　　　　 The man retired ______ teaching three years ago.

4)　　　　 Parents should reward children _______ their good behavior.

5)　　　　 They aimed to make the country safe _________ terrorist attacks.

6)　　　　 It is possible to disagree with people and still treat them _______ respect.

7)　　　　 My suitcase was so full that I didn’t have room ________ anything else.

8)　　　　 Lost in the desert, Mark went in search ___________ water

9)　　　　 He reminded me to return the books _______ the library on time.

10)　　 He jumped into the cold river and saved the child _______ drowning.

1． 单词拼写

1)　　　　 The teacher gave the children some chocolate to r___________ them for behaving well.

2)　　　　 Let’s go to that r__________ and try some Chinese food.

3)　　　　 I didn’t bother to cook and just had a ham s___________ for lunch. (三明治)

4)　　　　 The dustman collect the r_________ on Wednesdays.

5)　　　　 He did very well at math and won a s___________ to Cambridge University.

6)　　　　 We all have a r___________ to protect the environment. (责任)

7)　　　　 They’re working together to solve the r_____________. (谜语)

8)　　　　 The r___________ was launched from a space research base.

9)　　　　 This broadcast comes live via s_______________ from New York. (卫星)

10)　　 She works as a s___________ in a big international company. (秘书)

5．句子翻译

1)　　 价格降低了21%。(reduce)

2)　　 她拒绝接受他们的邀请。(refuse)

3)　　 现在用动物做实验被认为是很残忍的。(regard)

4)　　 在律师来之前他一直保持沉默。(remain)

5)　　 婴儿完全依赖别人喂食。(rely)

6)　　 这首歌曲让我想起了童年。(remind)

7)　　 我还记得爷爷跟我们做游戏的情景。(remember)

8)　　 如果你知道答案， 就请举手。(raise)

9)　　 药品应该放在小孩够不到的地方。(reach)

10) 这对夫妻经常为钱而吵架。(quarrel)

高三英语核心词汇复习第20课时

(see --- small)

4．选词填空

put　　 recover　 regular　 relief　　 replace　 quit　 receive　 reserve　 react　 remove

1)　　　　 She _____ no support from her parents; she had to rely on herself.

2)　　　　 He’s in hospital, ______ from a heart attack.

3)　　　　 Our _______ opening hours are from 10 am to 7 pm. On weekends we close at 5 pm.

4)　　　　 The old houses will be torn down and ______ with a shopping mall.

5)　　　　 Emma is not behaving very reasonably nowadays. I think she’s ______ against her teacher’s strictness.

6)　　　　 I didn’t recognize Tom until he ______ his dark sunglasses.

7)　　　　 To our ______, the missing boy finally came back home.

8)　　　　 It’s fairly risky. Or to ________ it another way, don’t try this at home.

9)　　　　 These seats are _______ for special guests.

10)　　 Doctors have given him six months to live if he doesn’t _______ drinking.

3．单项选择

1)　　　　 Lisa! I’m sorry --- I _______ recognize you --- you ________ your hair cut!

A. don’t; had　　　 B. didn’t; have had　 C. don’t; have had　 D. didn’t had

2)　　　　 The recording was __________. I can know exactly what happened at that time.

A. bad quality　　 B. good quality　　 C. of bad quality　 D. of good quality

3)　　　　 Buy vegetables _______ small quantities for your immediate use.

A. in　　 B. with　　 C. at　　 D. on

4)　　　　 Tanya, be __________! Our baby is sleeping and you may wake him up.

A. silent　　 B. still　　 C. quiet　 　D. noisy

5)　　　　 It remains ________ whether the operation was successful.

A. to be seen　　 B. to see　　 C. seeing　　 D. to have seen

6)　　　　 Australia’s unemployment ______ rose to 6.5% in February.

A. percent　　 B. rank　　 C. level　　 D. rate

7)　　　　 --- Can you see the sign on the door? --- Yes, it ________ “No Entry”.

A. reads　　 B. reflects　　 C. registers　 D. reports

8)　　　　 We regret _______ you that your application has not been successful.

A. informing　　 B. to inform　 C being informed　　 D. to have informed

9)　　　　 When the head teacher said someone didn’t obey the class discipline, we all knew whom he was ____________.

A. replying to　　 B. reacting to　　 C. referring to　　 D. relating to

10)　　 The terrible situation required that the manager ________ present.

A. be 　　　B. was　　 C. would be　 D. shall be

2．词形转换

1)　　　　 Alice read the letter with a __________ expression on her face. (puzzle)

2)　　　　 This part of the community needs to be protected from ______ prejudice. (race)

3)　　　　 Unexpectedly, he came to see me on a cold _______ day in October. (rain)

4)　　　　 I ______ that you are very busy, but could I talk to you for a few minutes? (realization)

5)　　　　 Tape ______ are widely used in English classes in China. (record)

6)　　　　 Be __________! You can’t expect her to do all the work on her own!(reason)

7)　　　　 Keep the file for future _________; it can be looked at in the future. (refer)

8)　　　　 My car’s quite old, but it’s still pretty ______________ (rely).

9)　　　　 It’s difficult to meet all the ________ of the strange customers. (require)

10)　　 Do something __________ before going to be --- read a book or take a hot bath. (relax)

1．单词拼写

1)　　　　 --- Three q______ of the money was spent on the program.　 --- 75%? Oh, my dear!

2)　　　　 Robin will take a general knowledge q_____________, and he’ll answer many difficult questions.

3)　　　　 Tracy works hard and makes r__________ progress in her studies.

4)　　　　 The PRC stands for the People’s R__________ of China.

5)　　　　 I have quite a good r___________ with my parents; we are very happy together.

6)　　　　 Frank’s dream of opening a restaurant became a r_________ in 1987. (现实)

7)　　　　 Each child had to r____________ a poem to the class. (背诵)

8)　　　　 Thanks to the R_______ and Opening-up Policy, China’s economy has improved a lot. (改革)

9)　　　　 We take all the old bottles to be r______________ (循环).

10)　　 He donated money to set up schools in r__________ mountain areas. (偏远的)

解法二　 设S_x＝Ax²+Bx(x∈N)

①－②，得A(m²－n²)+B(m－n)＝n－m

∵m≠n　 ∴ A(m+n)+B=－1

故A(m+n)²+B(m+n)＝－(m+n)

即S_m+n＝－(m+n)

说明　 a₁，d是等差数列的基本元素，通常是先求出基本元素，再

解的“整体化”思想，在解有关数列题目中值得借鉴．解法二中，由于是等差数列，由例22，故可设S_x=Ax²+Bx．(x∈N)

[例14]　 在项数为2n的等差数列中，各奇数项之和为75，各偶数项之和为90，末项与首项之差为27，则n之值是多少？

解　 ∵S_偶项－S_奇项=nd

∴nd=90－75=15

又由a_2n－a₁＝27，即(2n－1)d=27

[例15]　 在等差数列{a_n}中，已知a₁＝25，S₉＝S₁₇，问数列前多少项和最大，并求出最大值．

解法一　 建立S_n关于n的函数，运用函数思想，求最大值．

∵a₁=25，S₁₇＝S₉　 解得d＝－2

∴当n=13时，S_n最大，最大值S₁₃＝169

解法二　 因为a₁=25＞0，d＝－2＜0，所以数列{a_n}是递减等

∵a₁＝25，S₉＝S₁₇

∴a_n=25+(n－1)(－2)=－2n+27

即前13项和最大，由等差数列的前n项和公式可求得S₁₃=169．

解法三　 利用S₉=S₁₇寻找相邻项的关系．

由题意S₉=S₁₇得a₁₀+a₁₁+a₁₂+…+a₁₇=0

而a₁₀+a₁₇=a₁₁+a₁₆=a₁₂+a₁₅=a₁₃+a₁₄

∴a₁₃+a₁₄＝0，a₁₃=－a₁₄　 ∴a₁₃≥0，a₁₄≤0

∴S₁₃=169最大．

解法四　 根据等差数列前n项和的函数图像，确定取最大值时的n．

∵{a_n}是等差数列

∴可设S_n＝An²+Bn

二次函数y=Ax²+Bx的图像过原点，如图3．2－1所示

∵S₉＝S₁₇，

∴取n=13时，S₁₃＝169最大

4．关于几何概型：

(1)我们是就平面的情形给出几何概型的，同样的方法显然也适用于直线或空间的情形，只需将“面积”相应地改变为“长度”、“体积”；

(2)几何概型并不限于向平面(或直线、空间)投点的试验，如果一个随机试验有无限多个等可能的基本结果，每个基本结果可以用平面(或直线、空间)中的一点来表示，而所有基本结果对应于一个区域Ω，这时，与试验有关的问题即可利用几何概型来解决。

3．学好几何概率对于解决后续均匀分布的问题有很大帮助。