首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
In the past oysters were raised in much the same way as dirt farmers raised tomatoes—by transplanting them. First, farmers selec
In the past oysters were raised in much the same way as dirt farmers raised tomatoes—by transplanting them. First, farmers selec
admin
2012-05-17
75
问题
In the past oysters were raised in much the same way as dirt farmers raised tomatoes—by transplanting them. First, farmers selected the oyster bed, cleared the bottom of old shells and other debris, and then scattered clean shells about. Next they "planted" fertilized oyster eggs, which within two or three weeks hatched into larvae. The larvae drifted until they attached themselves to the clean shells on the bottom. There they remained and in time grew into baby oysters called seed or spat. The spat grew larger by drawing in seawater from which they derived microscopic particles of food. Before long, farmers gathered the baby oysters, transplanted them in other waters to speed up their growth, and then transplanted them once more into another body of water to fatten them up.
Until recently the supply of wild oysters and those crudely farmed were more than enough to satisfy people’s needs. But today the delectable seafood is no longer available in abundance. The problem has become so serious that some oyster beds have vanished entirely.
Fortunately, as far back as the early 1900’s marine biologists realized that if new measures were not taken, oysters would become extinct or at least luxury food. So they set up well equipped hatcheries and went to work. But they did not have the proper equipment or the skill to handle the eggs. They did not know when, what, and how to feed the larvae. And they knew little about the predators that attacked and ate baby oysters by the millions. They failed, but they doggedly kept at it. Finally, in the 1940’s a significant breakthrough was made.
The marine biologists discovered that by raising the temperature of the water, they could induce oysters to spawn not only in the summer but also in the fall, winter, and spring. Later they developed a technique for feeding the larvae and rearing them to spat. Going still further, they succeeded in breeding new strains that were resistant to diseases, grew faster and larger, and flourished in water of different salinities and temperatures. In addition, the cultivated oysters tasted better!
According to the passage, which of the following words best describes the efforts of the marine biologists working with oysters?
选项
A、Persistent.
B、Intermittent.
C、Traditional.
D、Fruitless.
答案
A
解析
细节题。选项A意思是“坚持不懈,持之以恒”,选项B意思是“间歇的,断断续续的”,选项C意思是“传 统一,选项D意思是“无结果的,不成功的”。在文中第三段,倒数第二句They failed,but they doggedly kept at it.(他们失败了,但是他们依然顽强地坚持。)句中用以形容海产学家努力的词是"doggedly”,意为“坚持不懈地”,与选项A中的Persistent意思相近。因此选择A。
转载请注明原文地址:https://kaotiyun.com/show/cxf7777K
0
大学英语四级
相关试题推荐
Ourape-menforefathershadnoobviousnaturalweaponsinthestruggleforsurvivalintheopen.Theyhadneitherthepowerful
Ourape-menforefathershadnoobviousnaturalweaponsinthestruggleforsurvivalintheopen.Theyhadneitherthepowerful
Allofusoughttobeabletobraceourselvesforthepredictablechallengesandsetbacksthatcropupinoureverydaylife.If
Computershavebeentaughttoactandspeak,buttheproblemishowto【C1】______themtolisten--tounderstandspokenwords.【C2】
Ilovetravelingbytrain.Fast【B1】______,slowlocaltrainswhichstopateverystation,【B2】______trainstakingbusinessmento
Therewasatimewhen,ifaladygotontoa【B1】______busortrain,agentlemanwouldimmediatelystandupandofferhisseat.No
ThereisprogresstowardapossibletreatmentforlungdiseasessuchasSARS(severeacuterespiratorysyndrome).Researchersha
DidtheAncientGreeksandRomanshaveasenseoffashion?Historiansofdresshavetraditionallyclaimedthatfashioninthemo
Themanagerurgedthathisstaff__________(不要错过这个机会).
Inordertoenlargethestudents’knowledge,theuniversityprovidesthestudentswith______(使用图书馆的机会).
随机试题
【背景资料】某办公大楼由主楼和裙楼两部分组成,平面呈不规则四边形,主楼29层,裙楼4层,地下2层,总建筑面积81650m2。该工程5月份完成主体施工,屋面防水施工安排在8月份。屋面防水层由一层聚氨酯防水涂料和一层自粘聚合物改性沥青防水卷
男,26岁。因发热、干咳、乏力30天,咯血2天入院。查体:T38.6℃,消瘦,左上肺触诊语颤增强,叩诊浊音,可闻及支气管呼吸音。PPD(1单位)硬结20mm,表面有水疱。X线胸片于左上肺2~4前肋处见密度高、浓淡不均阴影。最可能的诊断是(
男性,35岁,阑尾切除术后第1天,体温升高,大便次数增多,解黏液便,有里急后重,考虑并发了盆腔脓肿,首选的检验方法是
甲、乙、丙、丁、戊于2015年6月共同出资设立佳德有限责任公司,出资比例分别为50%、20%、15%、10%、5%,甲担任执行董事,乙担任经理,公司章程规定出资比例低于10%的股东不享有会计账簿查阅权。2018年6月丁将股权全部转让给丙,现乙、丙、丁、戊四
已知普通快滤池承托层高度为0.40m,滤料层厚度为0.70m,滤层上水深为1.80m,滤池超高一般取0.3m,滤池长度为12m,则滤池的高度为()m。
(2008年考试真题)贷记卡持卡人选择最低还款额方式用卡的,不再享受免息还款期待遇。()
导游人员带团时遇到了一位处处刁难的领队,在处理这个问题时,地陪的以下做法中哪个欠妥当?()
占人所谓在无他人监督的情况下,个人依然能够按照道德的规划和要求做人、做事的修养境界是()。
下面这篇文章是一个二年级学生所写的日记,请仔细阅读这篇习作,然后完成后面的题目。放鞭炮今天,夜晚我和爸爸、妈妈一起看见许多烟火,听到许多鞭炮声音,还放了一些烟火和鞭炮
设f(x)为连续函数,证明:
最新回复
(
0
)