首页
登录
职称英语
Sunlight is a great source of vitamin D in most of the world. Yet a (an)【C1】
Sunlight is a great source of vitamin D in most of the world. Yet a (an)【C1】
游客
2024-02-20
8
管理
问题
Sunlight is a great source of vitamin D in most of the world. Yet a (an)【C1】______number of experts think that many people aren’t getting enough vitamin D—【C2】______those who work and play indoors.
It’s long been known that vitamin D is【C3】______for strong bones. Research in the last several years has shown that low levels of vitamin D may increase the risk of heart【C4】______in men and deaths from some cancers. But new research suggests that it also protects against a wide【C5】______of diseases. Low levels of vitamin D have also been【C6】______with various forms of cancer and high blood pressure, stroke,【C7】______illness etc. The strongest source,【C8】______far, is ultraviolet (紫外线) B rays from the sun, which【C9】______a form of cholesterol (胆固醇) into vitamin D in the skin. But UVB rays【C10】______greatly depending on cloud cover, time of year and time of day. Dark-skinned and elderly people don’t【C11】______vitamin D from the sun as【C12】______as younger, fair-skinned people. UVB rays also don’t【C13】______glass or sunscreen with a factor of 8 or more. It’s difficult to get much vitamin D through diet. Few foods【C14】______it naturally. It’s widely【C15】______that most people need some supplemental vitamin D—the question is, how much? Current U. S. guidelines, issued in 1997,【C16】______for 200 international units from birth through age 50. The National Osteoporosis Foundation【C17】______adults over age 50 to get at least 800 to 1,000 IUs to【C18】______against fractures (骨折).
But as some experts research carry【C19】______the experiment, they worry that if people take too much vitamin D, it might act as a poison. Also, skin doctors warn people to be careful with sun【C20】______because of the risk of skin cancer. [br] 【C13】
选项
A、pierce
B、fluctuate
C、penetrate
D、reflect
答案
C
解析
动词辨义题。根据常识可知,防晒系数越高肯定防晒效果越好,紫外线不容易穿透,因此本句意为“UVB不能穿透防晒系数在8以上的玻璃或遮阳镜”,penetrate“渗透,穿透”符合题意。pierce“刺穿”;fluc一tuate“波动,动摇”;reflect“反映,反射,反省”,均不符合文意,故排除。
转载请注明原文地址:https://tihaiku.com/zcyy/3466089.html
相关试题推荐
Alandfreefromdestruction,pluswealth,naturalresources,andlaborsupp
Alandfreefromdestruction,pluswealth,naturalresources,andlaborsupp
Alandfreefromdestruction,pluswealth,naturalresources,andlaborsupp
Alandfreefromdestruction,pluswealth,naturalresources,andlaborsupp
Alandfreefromdestruction,pluswealth,naturalresources,andlaborsupp
Alandfreefromdestruction,pluswealth,naturalresources,andlaborsupp
Alandfreefromdestruction,pluswealth,naturalresources,andlaborsupp
Alandfreefromdestruction,pluswealth,naturalresources,andlaborsupp
Alandfreefromdestruction,pluswealth,naturalresources,andlaborsupp
Alandfreefromdestruction,pluswealth,naturalresources,andlaborsupp
随机试题
Theallusion"APoundofFlesh"comesfromShakespeare’s______.A、HamletB、TheM
以下属于水泥不合格现象的有( )。A.安定性不合格 B.化学成分不合格 C
一个网络可以由两台计算机组成,也可以由在同一大楼里面的上千台计算机组成。我们通常
根据《建筑工程建筑面积计算规范》GB/T503532013的规定,某厂房外墙勒
7d内起病的新生儿败血症最常见的感染来源是A.产前羊水穿刺后感染 B.产时,
A.泻下通便,行水消胀B.泻下逐水,杀虫C.泻下逐水,消肿D.行气利水,杀虫E.
某混凝土试块强度值不满足规范要求,但经法定检测单位对混凝土实体强度经过法定检测后
教师的工作目的和使命是()。 A.热爱教育事业B.热爱学生 C.教书育人
某税务师事务所税务师李某为外籍个人H先生代理个人所得税申报,由于税前扣除额计
银行承兑汇票的承兑银行,应当按照票面金额向出票人收取()的手续费。A:千分之一
最新回复
(
0
)