The "Daily Sentence" at the bottom of the page here [http://www.104learn.com.tw/language.htm] is a great way to get authentic Chinese sentences–and useful ones too; many you wouldn’t find in a normal textbook. What do I mean? They aren’t simplified down for FOREIGN readers, they’re written for NATIVE speakers and are a much better source for authentic Chinese sentences (to repeat myself).
Examples:
How，s it going? 近來如何？
Great! 很不錯！
How much does this cost? 這個值多少錢？
Sixty dollars. 六十元。
Excuse me. May I come in 抱歉，我可以進來嗎？
Sure. Come on in. 當然可以。進來吧。
Some of it may sounds very “dictionary”, but, hey, that just means when you’re using a Chinese to Chinese dictionary (which you should) it’ll be a lot easier.
And, if nothing else, the more sentences, the more variety, the more adaptive your language will be, like the Borg in Star Trek, which made them all the more intimidating. Be the Borg in Chinese (or whatever language you want to be).