Is there an online sample sentence database or search engine?

Sometime, I am not sure if I use a specific word correctly. I would like to get some sample sentences to learn from.

So, is there a online sample sentence database/search engine?

You could try using a corpus. For example, a search for copper in the British National Corpus returns 50 random sentences -- simply refresh the page to see another random sample:

http://bnc.bl.uk/saraWeb.php?qy=copper

Lots of dictionaries offer sample phrases. Merriam-Webster, Wiktionary, and the Free Online Dictionary come to mind. Complete sentences are usually provided to put expressions in context.

And then, of course, there is Google. It allows you to search for sample sentences by using the operators * (wildcard) and ~ (similar word or synonym). For example, if you are not sure which preposition to use in the phrase "he has not covered himself __ glory", you can use the search string "not ~covered * glory".

Use a corpus to help you. You can search for sentences with specific words, limit results by formality level (spoken, magazine, newspaper, fiction, academic), search by word class, and find common collocates for words, along with many other features. Here are some corpora:

• BYU Corpus Collection
• Corpus of Contemporary American English
• Corpus of Historical American English (COHA)
• BYU-BNC: British National Corpus
• TIME Corpus of American English.