If something's exact, it's precise and completely accurate — as opposed to a guess, an estimate, or an approximation.
Exact also has the meaning of taking something from someone, often money, and generally only given up with reluctance under the threat of force. The Mob might exact a shakedown from unfortunate businessmen, for example. The word comes from the Latin exactus "exact or accurate," a form of the verb exigere — meaning "to force out or demand," like the Mob demanding its money.
1.adj marked by strict and particular and complete accordance with fact
2.v take as an undesirable consequence of some event or state of affairs
archive
档案文件
v. 存档;
n. 档案文件; 档案室;
An archive is a collection of older things — documents, books, movies, or something else — that's meant to preserve them. Archives tell us about history.
档案馆是一个收集旧的东西-文件、书籍、电影或其他东西-这是为了保存它们。档案告诉我们历史。
An archive involves old stuff — specifically, a collection of old stuff, often put together by a librarian. Newspaper archives collect old newspapers, usually all copies of a paper from a certain date onward. There are movie and music archives. Most museums have many types of archives within them. And it's always a good idea to keep an archive of important files on your computer. When you put something in an archive, you're archiving it.
档案馆包括一些旧东西，特别是一些旧东西，通常由图书管理员整理。报纸档案馆收集旧报纸，通常是从某一日期起所有的报纸副本。有电影和音乐档案。大多数博物馆都有许多类型的档案。在你的电脑上保存重要文件的档案总是个好主意。当你把一些东西放进档案馆时，你就是在把它归档。
sanitary
卫生的
adj. 清洁的; 卫生的;
n. 公共厕所;
When something's sanitary, it's extremely clean. It's important for hospitals to be sanitary.
当某物是卫生的，它是非常干净的。医院必须保持卫生。
The adjective sanitary is useful when you need something stronger than just "clean." Sanitary implies the absence of germs as well as a clean appearance — you probably hope that your favorite restaurant's kitchen is sanitary, and your visiting friends will appreciate your bathroom being sanitary as well. The origin of sanitary is the Latin word sanitas, or "health," from the root sanus, which means both "healthy" and "sane."
当你需要比“干净”更强大的东西时，形容词“卫生”是有用的。卫生意味着没有细菌和干净的外观-你可能希望你最喜欢的餐厅厨房是卫生的，你的来访朋友也会欣赏你的浴室是卫生的。卫生的起源是拉丁词sanitas，或“健康”，从根sanus，这意味着“健康”和“健全”。
hassle
麻烦
n. 困难的事情; 麻烦的事情; 争论;
vt. 不断烦扰; 与…争辩; 使…烦恼;
vi. 争论，争辩;
Something that is bothersome or annoying can be called a hassle. It's a huge hassle to go back to the grocery story after unloading fifteen bags and realizing you forgot milk.
烦人或烦人的事情可以称为麻烦。在卸下15个袋子，意识到你忘了牛奶之后，回到杂货店的故事是一个巨大的麻烦。
The noun hassle can also refer to an argument or a scuffle. If you get into a hassle at school, you're likely to be called into the principal's office. As a verb, hassle means to annoy or harass repeatedly or chronically. If a bully is constantly hassling you, you should report them.
名词“hassle”也可以指论点或混战。如果你在学校遇到麻烦，你很可能会被叫到校长办公室。作为一个动词，hassle的意思是反复地或长期地骚扰或骚扰。如果一个恶霸经常骚扰你，你应该报告他们。
mushroom
蘑菇
n. 蘑菇; 蘑菇状物，蘑菇形物体; （女用）蘑菇形草帽; 暴发户;
adj. 蘑菇的; 蘑菇形的; 迅速生长的; 雨后蘑菇似的;
vi. 迅速增长; 采蘑菇; 迅速增加; （火）猛然的扩大;
A mushroom is the main body of a certain type of fungus. Edible mushrooms include portobellos and shiitakes. Don't mess around with the inedible types.
蘑菇是某种真菌的主体。食用蘑菇包括马齿苋和香菇。不要和不可食用的食物混在一起。
Walk in the woods after a few days of rain, and you're sure to see mushrooms growing from the damp forest floor. Mushrooms like moist environments, and many mushrooms also grow incredibly fast, which is where the verb form of mushroom, "grow and spread quickly," comes from. The word's origin is ultimately uncertain, although some experts believe it's related to the French mousse, or "moss."
substitution
替代 n. 代替; 代用; 替换; <化>取代（作用）;
The noun substitution refers to the act of replacing one thing with another. Your football coach might make a substitution by sending you onto the field to take over for a player who is tired or injured.
名词替换是指用一个事物替换另一个事物的行为。你的足球教练可能会派你到球场上接替一个疲惫或受伤的球员。
Substitution comes from the Middle French word of the same spelling, meaning "a putting in place of another." You might notice that substitution contains the root word substitute, and that's a good way to remember the meaning of the word. In school, a substitute is a temporary teacher who fills in when your regular teacher is out — in other words, a substitution has been made until your teacher returns.
替换来自拼写相同的法语中音单词，意思是“替换另一个”。您可能会注意到替换包含词根替换，这是记住单词含义的好方法。在学校里，代课老师是一个临时老师，当你的普通老师不在时，他会补课——换言之，在你的老师回来之前，代课老师都会补课。