写出下列卤代烃发生消除反应的主要产物。-|||-square square -|||-3)-|||-CH3-|||-Br NaOH-|||-square CH3CH2OH-|||-4)-|||-.(H)_(3)C(Cl)_(2)C(H)_(2)C(H)_(3)xrightarrow [C(H)_(3)C(H)_(2)OH