There are many free online resources which will help you to improve your English. This is a short list of some of the sites that I find very useful.

1. Free monolingual English dictionaries and a German-English online dictionary:

http://dictionary.cambridge.org/

http://www.businessdictionary.com/

http://dict.leo.org/

 

3. Other resources:

http://learnenglish.britishcouncil.org/en/

http://www.spotlight-online.de/language

http://www.business-spotlight.de/language-skills

http://www.ecenglish.com/learnenglish/

http://www.onestopenglish.com/business/

http://www.englishclub.com/business-english/

http://beo-businessenglishonline.wikispaces.com/

http://www.bized.co.uk/learn/index.htm

http://www.videovocab.tv/

http://www.cambridgeesol.org/exams/