单项选择题
住宅厨房与卫生间的门如不设固定百页，应留有一定进风措施，门下距地留出的缝隙不小于：
单项选择题 建筑物耐火等级共分几级以及二级耐火等级楼板的耐火极限分别为：
单项选择题 There()a dolphin show in the zoo tomorrow evening.A. wasB. will haveC. will be
单项选择题 For days, smog persisted in many areas. China is()to control air pollution.A. take measuresB. doing businessC. taking measures
