This depends on the precise radio frequency of the 21-cm wavelength, or 1420 megacycles per second.
这种通讯联系要靠21厘米波段,即每秒1420兆周的精确无线电频率。
新概念英语第四册 Lesson 43 Are there strangers in space

📚 句中词汇解析

从本句中提取的重要词汇

precise [prɪ'saɪs] 词频4 词根: pre
adj. 清晰的;精确的;正规的;精密;
💡 pre….前的,预先+cise切→预先切好的→精确的
"At that precise moment, Miss Pulteney came into the office."
就在那时, 普尔特尼小姐走进了办公室.
近义:pinpoint, accurate, correct, crisp, exact, pernickety 反义:indefinite, lax, loose, mistakable, sketchy, uncertain
radio ['redɪo] 词频2 词根: radi
n. 无线电;收音机;无线电广播台;无线电收发报机; vt.& vi. 用无线电发送讯息;作无线电广播;用X射线拍照;
💡 radi 表”射线,辐射,广播”
"The President gave an address to the nation over the radio."
总统向全国发表广播演说.
近义:transmit, radiophonics, radiotelephony
frequency ['frikwənsi] 词频5 词根: frequen
n. 频繁性;[数][物]频率,次数;频率分布;
💡 fr + equ =equal,even,表示“相等,平均” + enc + y [形容词后缀] → n.屡次;次数;频率
"Fatal road accidents have decreased in frequency over recent years."
近年来致命交通事故发生率已经下降。
近义:assiduity, periodicity, regularity, chronicity 反义:uncommonness
wavelength ['wevlɛŋθ]
n. <物>波长;波段;完全一致,融洽;
💡 wave波+length长度 → 波长
"Radio One has broadcast on this wavelength for years."
广播1台已经用这个波长广播多年了.
近义:w.l.
second ['sɛkənd] 词频1 词根: 跟随
n. 秒;瞬间;次货;第二份食物; adj. 第二的;次要的;居第二位的;另外的; adv. 第二;其次;以第二位; vt. 支持;临时调派;附议;赞成提案;
💡 sec跟随+ond=one第一→跟随第一个之后→第二;秒
"She was in the second year of her apprenticeship as a carpenter."
她当木工学徒已是第二年了。
近义:back, backstop, reinforce, support, advocate, endorse 反义:oppose, confront, contradict, counter, fence

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