裂化是指有机化合物在高温下分子发生分解的反应过程，分为热裂化、催化裂化、加氢裂化。热裂化存在的主要危险性是（ ）。
A．裂化过程产生大量的裂化气，遇明火会发生爆炸
B．裂化过程中，活化催化剂不正常时，可能出现可燃的一氧化碳气体
C．裂化过程中，若温度过高或落人少量水，容易引起突沸冲料或爆炸
D．裂化过程中，生成过氧化物副产物，它们的稳定性差，遇高温或受撞击、易分解，造成燃烧或爆炸
参考答案：A
| It sounds like a science fiction, but researchers say it’s a scientific fact: Microscopic organisms dubbed "killer algae" are paralyzing fish with unknown toxins and then eating away at their flesh. They might be making people sick, too. The name given to this single-cell organism, or dinoflagellate, is Pfiesteria piscimorte—literally, "fish killer." It was discovered at North Carolina State University in 1988, but at the same time, few scientists believed in its existence, much less in its highly unusual predatory nature. But ongoing research has led to international acknowledgment of the phenomenon and, recently, research funding. Seemingly prompted by an unknown substance secreted by fish, the aggressive creature swims into action. It sends neurotoxins into the water and air, paralyzing a fish’s nervous system, and causing it to gasp for air at the surface. Eventually the fish suffocates. The killer dinoflagellate then attaches itself to the fish and begins sucking away at its flesh. This macabre scenario may help solve several sea mysteries, such as why fishermen report seeing "fish walks" (fish trying to leave the water) and pools of dead fish with holes eaten through them. Whether humans are affected by the dinoflagellate’s toxin remains to be seen. Researchers think it’s unlikely eating fresh fish are in danger, but anyone with frequent exposure to the creature could be in peril. Several researchers working with the algae have reported bouts of memory loss and disorientation. To understand the killer algae further, scientists must fully characterize their toxin and determine what stimulates them to attack. They also need to know if the algae are hurting fish populations, and whether pollutants make them more likely to attack. |
The word "literally" underlined in Paragraph 2 most probably means ______ .
A．namely
B．superficially
C．imaginatively
D．actually