Good morning, it's Friday, December 20th and here are the Five Things You Must Know Before the Market Opens, presented by The Street: First up, Stock Futures Dip After More Wall Street Records U.S. stock futures dipped Friday, pulling Wall Street below the all-time highs that were set in the previous session after Treasury Secretary Steven Mnuchin said the U.S. and China would sign their "phase one" trade agreement in early January.