Possibly Line dictionary (replaced the amazing nciku) http://linedictionary.naver.com/dict.html#/cnen/home

[1] nciku http://www.nciku.com Apparently now http://linedictionary.naver.com/dict.html#/cnen/ ? [2] zdic (http://www.zdic.net) mostly for CN-CN, but also has some English [3] 愛詞霸 http://www.iciba.com

eudic.net There's also an app version for OS X and Android system. But it's just a dictionary and did not provide sentence translate service.

A good app is Pleco Best dictionary ever It's free too

1.youdao.com,有道词典 2.Bing必应