Is "be careful crossing that bridge" a complete or fragment sentence?

Which of the following lines contains a simile? you wet brown bag of a womani think that i shall never see/ a poem lovely as a treebecause i could not stop for death/ he kindly stopped for mea little learning is a dangerous thing

You suspect that this article has left out some facts that might lead the reader to believe that someone else made the star-spangled banner. what is the best way to verify this? by consulting a variety of sources by disregarding the article entirely by writing a letter to the editor of the publication that printed the article by reading various historical accounts by verifying the opinions

Read the quote from zimmermann in the code book. a future government could inherit a technology infrastructure that's optimized for surveillance, where they can watch the movements of their political opposition, every financial transaction, every communication, every bit of e-mail, every phone call. everything could be filtered and scanned and automatically recognized by voice recognition technology and transcribed. it's time for cryptography to step out of the shadows of spies and the military, and step into the sunshine and be embraced by the rest of us. which question does this paragraph answer? why does zimmermann think encryption is important? what kind of encryption did zimmermann invent? how does zimmermann’s encryption work? who made encryption based on zimmermann’s work?