钙质生石灰和镁质生石灰的技术指标是根据______确定的。
A.CaO+MgO的含量
B.未消化残渣含量
C.有效MgO的含量
D.有效CaO+MgO的含量
参考答案:B,D
当燃气炉具失火时,首先必须拿二氧化碳灭火器灭火。()
The teacher says we _____read ______ comic books.
A.mustn’t, much too
B.can’t, much too
C.may not, too many
D.shouldn’t, too many