摘要:
小编为大家整理了全网最全托福TPO1-25综合写作文本,希望帮助考生更好的备考,争取理想成绩,实现留学梦想。下面是托福TPO23写作 部分。
TPO 23
Reading
Populations of the yellow cedar, a species of tree that is common in northwestern North America, have been steadily declining for more than a century now, since about 1880. Scientists have advanced several hypotheses explain this decline.
One hypothesis is that the yellow cedar decline may be caused by insect parasites, specifically the cedar bark beetle. This beetle is known to attack cedar trees; the beetle larvae eat the wood. There have been recorded instances of sustained beetle attacks overwhelming and killing yellow cedars, so this insect is a good candidate for the cause of the tree’s decline.
A second hypothesis attributes the decline to brown bears. Bears sometimes claw at the cedars in order to eat the tree bark, which has a high sugar content. In fact, the cedar bark can contain as much sugar as the wild berries that are a staple of the bears’ diet. Although the bears’ clawing is unlikely to destroy trees by itself, their aggressive feeding habits may critically weaken enough trees to be responsible for the decline.
The third hypothesis states that gradual changes of climate may be to blame. Over the last hundred years, the patterns of seasonal as well as day-to-day temperatures have changed in northwestern North America. These changes have affected the root systems of the yellow cedar trees: the fine surface roots now start growing in the late winter rather than in the early spring. The change in the timing of root growth may have significant consequences. Growing roots are sensitive and are therefore likely to suffer damage from partial freezing on cold winter nights. This frozen root damage may be capable of undermining the health of the whole tree, eventually killing it.
Listening
Unfortunately, we still don’t know what’s killing the yellow cedar, none of the explanations discussed in the reading is adequate.
First, the cedar bark beetle. Well, the problem with this explanation is that healthy yellow cedars are generally much more resistant to insect infestation than other tree species. For example, the bark and leaves of yellow cedar are saturated with powerful chemicals that are poisonous to insects. So, healthy cedars are unlikely to suffer from insect damage. So, how can we explain those dead cedars that were infested with beetles. In those cases, the beetles attack trees that were already damaged or sick, and would’ve probably died anyway. So, the beetles are not the fundamental cause responsible for the decline of yellow cedars.
Second, although bears damage some trees, they’re not the cause of the overall population decline. Yellow cedar population’s been declining all across the northwestern coast of North America both on the mainland and on islands just off the coast. There were no bears on the islands, yet the islands cedars are still in decline. Since the decline occurs with and without bears, the bears cannot be responsible.
And finally, the theory about roots suffering from frost damage, well, the reading passage forgot to take one factor into account. Many more trees are dying at lower elevations where it is warm than at higher elevations where it is cold. If freezing damage were responsible for the decline, we could expect to see more trees dying in the cold weather of higher elevations. Instead, more trees are dying in the relative warmth of the lower elevations. So, although the climate change may have made the cedar roots more sensitive than it used to be, this isn’t what’s killing them.
免费领取最新剑桥雅思、TPO、SAT真题、百人留学备考群,名师答疑,助教监督,分享最新资讯,领取独家资料。
方法1:扫码添加新航道老师
微信号:shnc_2018
方法2:留下表单信息,老师会及时与您联系
课程名称 | 班级人数 | 课时 | 学费 | 报名 |
---|---|---|---|---|
托福入门段(A段)6-10人走读班 | 6-10人 | 80课时 | ¥15800 | 在线咨询 |
托福强化段(C段)6-10人班 | 6-10人 | 96课时 | ¥30800 | 在线咨询 |
托福全程段(A+B+C段)6-10人班 | 6-10人 | 192课时 | ¥55800 | 在线咨询 |
托福特训班(4周,走读) | 8-10人 | 192 | ¥34800 | 在线咨询 |
托福特训班(6周,走读) | 8-10人 | 288 | ¥49800 | 在线咨询 |
课程名称 | 班级人数 | 课时 | 学费 | 报名 |
---|---|---|---|---|
托福精讲段(B段)20-30人班 | 20-30人 | 96课时 | ¥8800 | 在线咨询 |
托福强化段(C段)20-30人班 | 20-30人 | 96课时 | ¥7800 | 在线咨询 |
托福全程段(A+B+C段)20-30人班 | 20-30人 | 192课时 | ¥13800 | 在线咨询 |
课程名称 | 班级人数 | 课时 | 学费 | 报名 |
---|---|---|---|---|
托福入门段(A段)(6-10人,住宿) | 6-10人 | 80课时 | ¥17800 | 在线咨询 |
托福强化段(C段)6-10人班住宿 | 152课时 | ¥33800 | 在线咨询 | |
托福全程班(A+B+C段)6-10人班住宿 | 6-10人 | 304课时 | ¥60800 | 在线咨询 |
托福长线班(6-10人,住宿) | 6-10人 | 272课时 | ¥77800 | 在线咨询 |
托福词汇语法住宿班(A段)(6-10人) | 6-10人 | 48课时 | ¥8800 | 在线咨询 |
课程名称 | 班级人数 | 课时 | 学费 | 报名 |
---|---|---|---|---|
托福全程段(A+B+C段)20-30人班住宿 | 20-30人 | 192课时 | ¥15800 | 在线咨询 |
托福强化段(C段)20-30人班住宿 | 20-30人 | 96课时 | ¥8800 | 在线咨询 |
托福精讲段(B段)20-30人班住宿 | 20-30人 | 96课时 | ¥9800 | 在线咨询 |
课程名称 | 班级人数 | 课时 | 学费 | 报名 |
---|---|---|---|---|
托福一对一 | 1 | 按需定制 | ¥980元 | 在线咨询 |
托福免费试听课 | ¥0元 | 在线咨询 |
课程名称 | 班级人数 | 课时 | 学费 | 报名 |
---|---|---|---|---|
小托福课程 | 6人 | 54小时 | ¥20800 | 在线咨询 |
小托福考试技巧进阶课程 | 30 | ¥9800 | 在线咨询 |
免责声明
1、如转载本网原创文章,请表明出处;
2、本网转载媒体稿件旨在传播更多有益信息,并不代表同意该观点,本网不承担稿件侵权行为的连带责任;
3、如本网转载稿、资料分享涉及版权等问题,请作者见稿后速与新航道联系(电话:021-64380066),我们会第一时间删除。
地址:徐汇区文定路209号宝地文定商务中心1楼
乘车路线:地铁1/4号线上海体育馆、3/9号线宜山路站、11号线上海游泳馆站
总部地址:北京市海淀区中关村大街28-1号6层601 集团客服电话:400-097-9266 总部:北京新航道教育文化发展有限责任公司
Copyright © www.xhd.cn All Rights Reserved 京ICP备05069206