One disadvantage of using regular dry chemical (sodium bicarbonate) in firefighting is that（）.

A.it can break down under high heat and emit noxious fumes

B.it will decompose under prolonged storage and lose its effectiveness

C.fire has been known to flash back over the surface of an oil fire

D.it is ineffective in fighting fires in high-voltage electrical equipment

类白血病反应的特点是（）

A.骨髓中幼稚粒细胞增高

B.外周血出现幼稚细胞，NAP活性增高

C.外周血白细胞>50×10⁹/L

D.脾脏显著肿大

E.外周血嗜碱、嗜酸粒细胞增高