http://wenku.baidu.com/view/c45d623610661ed9ad51f371
grammar check website:
http://www.spellcheck.net/
http://www.grammarly.com/ (charged)
grammar check tool:
1checker
http://wps.pearsoned.co.uk/ema_uk_he_matthews_resmeth/153/39239/10045208.cw/content/index.html
同义词替换