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
The human heart is enclosed in a sac with a two-layered wall. A lubricating fluid fills the space between the two walls, enablin
The human heart is enclosed in a sac with a two-layered wall. A lubricating fluid fills the space between the two walls, enablin
admin
2019-07-01
37
问题
The human heart is enclosed in a sac with a two-layered wall. A lubricating fluid fills the space between the two walls, enabling them to slide past each other as the heart pulsates. The heart is mostly cardiac muscle tissue divided into four chambers, two atria and two ventricles. The atria have relatively thin walls and function as collection chambers for blood. The ventricles have thicker walls and are much more powerful than the atria, especially the left ventricle, which must pump blood to all organs of the body. A When the heart beats, the ventricles contract and pump blood. As the heart relaxes after a contraction, the atria fill with blood. B One complete sequence of pumping and filling is called the cardiac cycle. C In an average adult at rest, the cycle takes about 0.8 second. The number of times the heart beats each minute is the heart rate, which can be measured by taking the pulse. D On average, a healthy adult at rest has a heart rate of about 70 beats per minute. An individual’s heart rate will vary, depending on the level of activity.
Look at the four squares, A, B, C, and D, which indicate where the following sentence could be added to the passage. Where would the sentence best fit? The pulse is the rhythmic stretching of the arteries caused by the pressure of the blood when the ventricles contract.
选项
A、
B、
C、
D、
答案
D
解析
The added sentence defines pulse, which develops the phrase taking the pulse, introduced in the previous sentence.
转载请注明原文地址:https://kaotiyun.com/show/zifO777K
0
托福(TOEFL)
相关试题推荐
Completethenotesbelow.WriteNOMORETHANTWOWORDSforeachanswer.TheroleofsleepinhumansandanimalsImportanceofsl
Choosethecorrectletter,A,BorC.LabelsgivingnutritionalinformationonfoodpackagingJackprefersthedailyvaluesyst
Completethenotesbelow.WriteONEWORDONLYforeachanswer.Episodicmemory-theabilitytorecalldetails,e.g.thetimeand
ChooseTWOletters,A-E.WhichTWOsubjectsdidMartinalikebestbeforegoingtouniversity?AArtBHistoryCFrenchDEnglish
safe本题有关卫生城市的标准。and连接两个并列形容词,一同修饰环境。录音原文用定语从句的形式(acleanenvironmentwhichis…)替换了题目中的并列结构。
Beesthathelpwithpollinationbenefitflowersand【L31】________.Beesproducewaxthatcanbemadeintocandlesand【L32】______
Whatdoesthepassagemainlydiscuss?Accordingtothepassage,whatisonedifferencebetweenthehuntingdonebysomehumans
A、Shepreferstoremainindoors.B、Shehasthesameallergiesthatthemanhas.C、Shedoesn’tthinkthemanissincere.D、Shedo
NativeAmericansprobablyarrivedfromAsiainsuccessivewavesoverseveralmillennia,crossingaplainhundredsofmilesw
A、ShepreferstostayindoorsduringthesummerB、Shedoesn’tagreewiththemanC、ToomuchhotweathercanbeunpleasantD、The
随机试题
Howwilltheyadvertisetheirproduct?
提出美就是“绝对理念的感性显现”这一命题的是【】
A.间羟胺B.异丙肾上腺素C.克仑特罗D.吗啡E.氨茶碱对β2受体选择性差,大剂量可致心律失常的药物是
建筑师初始注册者可以自执业资格证书签发之日起()年内提出申请。
企业法人:是指具有符合国家法律规定的资金数额、企业名称、组织章程、组织机构、住所等法定条件,能够独立承担民事责任,经主管机关核准登记取得法人资格的社会经济组织。据此定义,下列属于企业法人的是()。
六个城市中二氧化硫治理最好的城市是哪个?()沈阳市工业二氧化硫去除量占工业二氧化硫产出量的比例是()。
在公民的各项政治自由中,属于首要地位的是()
以下列举的主体,不享有选举权的是()
按照嵌入式系统的技术复杂程度进行分类,可以把嵌入式系统分为低端系统、中端系统和高端系统三大类。下面关于高端嵌入式系统特性的叙述中错误的是()。
A、Allowchildrentofindouttheirownmistakes.B、Pointoutchildren’smistakeswhenevertheyarefound.C、Correctchildren’sm
最新回复
(
0
)