在线英语词典

https://www.dictionary.com/

https://dictionary.cambridge.org/

https://www.merriam-webster.com/

https://www.collinsdictionary.com/
(https://www.collinsdictionary.com/zh/)

以上词典都可查询单词的发音。

http://dict.youdao.com/

http://www.iciba.com/

https://www.91dict.com/  (感觉91dict.com比iciba.com好用）

https://www.vocabulary.com/dictionary/ 

https://idioms.thefreedictionary.com/