高中英语外研版 (2019)选择性必修 第二册Unit 5 A delicate world完美版ppt课件

这是一份高中英语外研版 (2019)选择性必修 第二册Unit 5 A delicate world完美版ppt课件，共22页。PPT课件主要包含了 absorb， rely on ，preyed on ， feed on， release等内容，欢迎下载使用。

Part 1 Grammar
Study the rule f it as empty bject
a. N visitrs wuld think it surprising that the island is a UNESCO Wrld Heritage Site. b. N visitrs wuld think that island being a UNESCO Wrld Heritage Site is surprising.
1. What des “it” refer t in sentence (a) ?
In sentences (a) refers t “that the island is a UNESCO Wrld Heritage Site”
c. Experts felt it necessary t cme up with a plan t remve all the rabbits frm the island. d. Experts felt t cme up with a plan t remve all the rabbits frm the island was necessary.
2. What des “it” refer t in sentence (c) ?
In sentences (c) refers t “t cme up with a plan t remve all the rabbits frm the island ”
Cmpare the sentences in each grup
3. What is the difference between the sentences in each grup?
In the 1st grup, the bject f the 1st sentence is replaced by “it”, whileIn the 2nt sentence, the bject clause is in the psitin f the bject.
In the 2nd grup, the bject f the 1st sentence is replaced by “it”, whilein the 2nd sentence, the infintive is in the psitin f the bject.
Mre sentences with it as an empty bject
1. This incident made it clear that the rat, muse and rabbit prblem needed slving nce and fr all. 2. we humans we it t the island t give it a happy ending.
Ntes: T balance sentence structure, the auther used an empty bject t replaces t lng infinitive structures r bject clause.
Rewrite the underlined parts using it as an empty bject.
1. Due t its cute appearance, many peple think keeping this turtle as a pet is a gd idea.2. and sme wners believe t release them int the wild is n big issue.
Due t its cute appearance, many peple think it a gd idea t keep this turtle as a pet is
and sme wners believe it n big issue t release them int the wild.
3. These days, peple have fund t release these turtles int the wild is a threat t ther species.4. Experts cnsider wners keeping their pets in an enclsed area imprtant
These days, peple have fund it a threat t ther species t release these turtles int the wild.
Experts cnsider wers it imprtant fr wners t keep their pets in an enclsed area.
Practice 2
Describe the changes happening t the parks, using it as an empty bject.
the Saihanba Natinal Frest Park
eg. I think it a breakthrugh t transfrm a desert int a frest.
Pssible answers: 1. I believe it likely that mre vlunteers will help plant mre trees arund the park.
2. I find it impssible t investigate all the living species in the park at present.
3. I feel it unrealistic fr the lcal peple t grw rice and wheat fr gian industry.
Befre listening
Fd chains andenergy exchange
Decmpsers break dwn dead animial and vegetable matter int nutrients. The disslved chemicals are then released back int the fd chain, t be used by prducers.
1. What des the diagram shw?2. What are the relatinships between the living things?
Everything in the wrld is related t each ther.
Creatures in nature depend upn each ther and cexsit with each ther.
Talk abut ecsytems
Listen t the cnversatin and chse the true statements.
1. Bees are very imprtant t ur fd supply because they prvide hney. 2. The bee ppulatin is declining. 3. Withut bees, humans wuld die ut. 4. All human crps depend n bees fr pllinatin. 5. If bees becme extinct, ther insects culd pllinate enugh crps. 6. Humans are respnsible fr the decline in the bee ppulatin.
Yur answer: ____________
Knw mre abut ecsytems
IN a wdland ecsytem, trees and ther plants are prducers. They 1. ___________ water, and take in nutrients frm the sil and energy frm the sun. Insects are an example f a primary cnsumer. They 2. ________the prducers t prvide fd fr them, and are 3. ______________ by secndary cnsumers: small mammals and birds. They 4. __________ the primary cmsumers. wrms, fungi and bacteria are decmpsers. They 5. _____________ animals waste and the remains f the living things. The chemicals these decmpsers 6 ___________ fertilise the sil and give the plants the nutrients they need t grw.
break dwn
Pst listening 1
Learn hw t express yur dubt r respnd t dubt.
Expressing dubt
Respnding t dubt
1, 2, 5
3, 4, 6, 7
Pst listening 2
Wrk in pairs. Talk abut what wuld happen t the ecsytem if anther species died ut.
Reference: Every rganism plays an irreplaceable rle in the ecsystem, even the muse r a kind f pests. The extinctin f ne rganism may lead t the lack f fd fr thers, while sme rganisms may lse their natural enemies and have uncntrlled numbers, thus affecting the whle ecsystem and the whle bisphere.
Listen again
Language appreciatin
1. Recent years have seen mre and mre pet sliders escaping r being released frm hmes. •[句式分析] 本句主谓部分采用“时间+ have seen”, 其中see意为“见证经历”， 注意主谓人称数的一致性； see sb/sth ding 表示看见正在进行，see sb/sth being dne表示看见正在被执行的动作。 •[尝试翻译] 近年来，越来越多的宠物龟逃出家门或被放生。
2. In just ne jurney t cllect pllen and nectar, ne single hney bee pllinate as many as 50 t 100 flwers. •[句式分析] 句中“t cllect pllen and nectar”为不定式短语作后置定语，修饰其前面的名词； as many as +数量+ 名词 表示“多达”, 强调数量之多。 •[尝试翻译] 在一次采集花粉和花蜜的旅程中，一只蜜蜂授粉多达50到100朵花。
Language pints
Assignments fr this perid
1. Review the vcabulary and the language pnits f the text. 2. Listen t the material Page 7 nce mre and get mre infrmatin . 3. Write a shrt passage abut impacts f species extinctin.