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：

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：A.四级，1.5hB.三级，1.OhC.四级，2....

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：

There()a dolphin show in the zoo tomorrow evening.A. wa...

单项选择题There()a dolphin show in the zoo tomorrow evening.
A. was
B. will have
C. will be

For days, smog persisted in many areas. China is()to co...

单项选择题For days, smog persisted in many areas. China is()to control air pollution.
A. take measures
B. doing business
C. taking measures