情态动词:can与could的用法详解 一、表示能力 (1) 表示现在的能力，用can： My sister can drive. 我妹妹会开车。 Everyone here can speak English. 这儿人人会说英语。 (2) 表示将来的能力，通常不用can或could… In this example, can is used to ask for or give permission to do something. Can I go for lunch, Elly? Yes, of course you can, James! Oh, thank you. Learning a language can be difficult. In this final example, can is used to talk about possibility. Elly, take a jacket! It can get cold at night! OK, thanks James. Can是英语中的多功能词汇，具有情态动词与名词双重词性，发音为英 [kæn; kən]、美 [kæn; kən]。 其词源可追溯至古英语“cunnan”，原意为“知道、有能力”。 Canva is a free-to-use online graphic design tool. Use it to create social media posts, presentations, posters, videos, logos and more. You probably think college students are experts at sleeping, but parties, preparations for tests, personal problems and general stress can wreck a student’s sleep habits, which can be bad for the body and the mind. can 和 can’t 是最常见的情态动词，用来表达能力、许可与可能性。 本篇详细说明句型结构、否定与疑问形式、常见错误与实用例句，并附练习题，帮助你完整掌握 can 的用法。 1. CAN总线 历史 CAN 是 Controller Area Network 的缩写（以下称为 CAN），是 ISO国际标准化的串行通信协议。 在当前的汽车产业中，出于对安全性、舒适性、方便性、低公害、低成本的要求，各种各样的电子控制系统被开发了出来。 Can is usually used in standard spoken English when asking for permission. It is acceptable in most forms of written English, although in very formal writing, such as official instructions, may is often used instead: Persons under 14 unaccompanied by an adult may not enter. The use of can to ask or grant permission has been common since the 19th century and is well established, although some feel may is more appropriate in formal contexts. May is relatively rare in negative constructions (mayn't is not common); cannot and can't are usual in such contexts. I don't know how he can afford a new car on his salary. Cats can see in the dark. The water's not deep here - look, I can touch the bottom. I doubt whether I can finish the work on time. Computers can perform millions of calculations every second.