Ethanol is more effective at a concentration of 50-70 percent;
乙醇的浓度为50％至70％时比较有效，
新概念英语第四册 Lesson 38 Water and the traveller

📚 句中词汇解析

从本句中提取的重要词汇

effective [ɪ'fɛktɪv] 词频2 词根: fac
adj. 有效的;起作用的;实际的，实在的;给人深刻印象; n. [军]现役兵额，有生力量，精兵;
💡 ef出+fect做，制作 +ive形容词后缀 →做出来的 → 有效的
"The police bandobast was very effective."
警方的安排十分奏效。
近义：curative, curing, helpful, assistive, operating, operative 反义：incapable, ineffective, ineffectual, inefficacious, inept, inexpert
concentration ['kɑnsn'treʃən] 词频2 词根: con
n. 集中;专心;关注;浓度;
💡 con共同+centr中心+ation后缀→集中；浓缩
"This book requires a great deal of concentration."
这本书需要全神贯注才能读懂。
近义：throng, confluence, crowd, heedfulness, application, intentness 反义：dissolution, dissolving, impoliteness, inattention, inattentiveness, absentmindedness
percent [pɚ'sɛnt] 词根: cent
n. 百分比，百分数;百分之一; adj. 百分之…的，每一百中有…的;百分之…支付利息的; adv. 以百分之…地，每一百中有…地;
💡 per贯穿，自始自终+cent一百→百分比
"A conflagration in 1947 reduced 90 percent of the houses to ashes."
1947年的一场大火,使90%的房屋化为灰烬.
近义：percentage, part, portion, fragment, cud, quid
ethanol
n. 乙醇, 酒精\\n[化] 乙醇

📚 更多「新概念英语第四册」例句

Anyone who has played even in a school football match knows this.
即使是仅仅参加过学校足球赛的人也有种体会。
because they are unwilling to have their names entered as having taken out such and such a book,
因为它们不愿让人家记下它们公司的名字和借阅的某一本书。
The albatross is the king of the gliders, the class of fliers which harness the air to their purpose, but must yield to its opposition.
信天翁是滑翔飞行的鸟类之王，它能自如地驾驭空气，但必须顺气流飞行。
From the shore line, out to a distance which may be anywhere from a few miles to a few hundred miles,
从海岸线向大海延伸几英里到几百英里的区域是大陆架慢坡，
lawyers and defendants, marriages and births----
律师和被告、婚姻和生育，
and another 700 for the survivors to be reduced by half again.
剩下的一半人再过700年，才会又减少一半。