It's too late for school. I don't know _____.    [ ]

A. what to do that

B. how to do

C. what to do

D. how to do it

依据现行的《钢结构防火涂料》规定，检测项目属于B类缺陷是（）

A、在容器中的状态 

B、粘结强度 

C、干燥时间 

D、外观与颜色