This formula is satisfiable because if we set to b to true and a to false, then the whole formula is true. All other assignments make the formula false, but it doesn't change that the formula is satisfiable as long as there is at least one assignment makes the formula true.
在地处热带的冈比亚中河区广袤原野上，炽热的阳光照耀着一片无垠的金色海洋。微风拂过，稻穗轻轻晃动，稻叶沙沙作响。看着眼前的马鲁奥农场，农场主穆萨·达博欣喜不已：“这预示着又一个丰收季节。”，详情可参考91视频
Which fonts are most dangerous?。关于这个话题，safew官方版本下载提供了深入分析
蜡梅的“蜡”字源于其花瓣质地如涂蜡一般。在植物学界文献和专业书籍里，大多采用“蜡梅”二字。