A city divided by a gap in healthy life expectancy
宜昌人对蜡梅的喜爱，印在了年年岁岁的记忆里。作为传统的年宵花，春节前后，郊区农民剪下自家的蜡梅花枝进城出售，很快就会销售一空。捧着造型独特的蜡梅花枝回家，选个好看的花瓶插上，淡淡的清香弥散开来，新春的氛围一下子就浓了。
，这一点在同城约会中也有详细论述
There is a special form for boolean formulas called "Conjunctive Normal Form" (CNF). A problem in this form consists of clauses connected with and operators, where each clause only contains variables connected with or operators. The variables can appear negated, but only variables can be directly negated, something like !(a && b) is not allowed. An example boolean formula in CNF form is:
items in it. append can just place the item in the existing backing