想留言，如介绍好工具，请在二楼留言，其他楼保留，谢谢合作......

http://corpus.byu.edu/coca/
THE CORPUS OF CONTEMPORARY AMERICAN ENGLISH(COCA)
450 MILLION WORDS, 1990-2012

The Corpus of Contemporary American English (COCA) is the largestfreely-available corpus of English, and the onlylarge and balanced corpus of American English. The corpus was created byMark Daviesof Brigham Young University,and it is used bytens of thousandsof users every month (linguists, teachers, translators, and otherresearchers).
The corpus contains more than 450million words of text and is equally divided among spoken, fiction, popular magazines,newspapers, and academic texts. It includes 20 million words each year from1990-2012 and thecorpus is also updatedregularly (the most recent texts are fromSummer 2012).Because of its design, it is perhaps the onlycorpus of English that is suitable for looking atcurrent, ongoing changes in thelanguage

http://www.natcorp.ox.ac.uk/
语库/英式英语
BRITISH NATIONAL CORPUS (BNC)

About the BNC
The British National Corpus (BNC) is a 100 million word collection of samples of written and spoken language from a wide range of sources, designed to represent a wide cross-section of current British English, both spoken and written.

http://www.memidex.com/
MEMIDEX

Memidex is a free online dictionary and thesaurus with a simple interface, complete inflections, auto-suggest, adult-filtering, frequent updates, a browsable index, support for mobile devices, and millions of external reference links for definitions, audio, and etymology. It's fast too. Use the Find box for exact matching or browse using the complete index.

http://www.collinsdictionary.com/english-thesaurus
COLLINS ENGLISH THESAURUS

English Thesaurus
Pioneers in dictionary publishing since 1819

PRO Writing Aid Free Online Collocations Dictionary
http://prowritingaid.com/Free-Online-Collocations-Dictionary.aspx

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https://books.google.com/ngrams