Example: You should read it carefully before ____. (sign, deal) You should read it carefully before signing the deal . Linda talked to an insurance agent for many times before (make, final decision)
【简答题】The IR spectrum of an organic molecule,C4H8O,shows absorptions at 755,945,1080,1180,1370,1425,1725 and 2950cm-1.What is the probable structural formula for the molecule?