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问题 单项选择题

对发行债券的说法中不正确的是( )。

A．企业债券融资是一种直接融资
B．发行债券的企业必须实力很强，资信良好或有很强的第三方担保
C．发行债券通常需要取得债券资信等级的评级
D．债券只能在公开的资本市场上公开发行

答案

参考答案：D

解析：债券可以在公开的资本市场上公开发行，也可以以私募方式发行。

计算题

一辆小汽车，匀速通过70m长的桥用了10s，它以同样的速度通过另一座桥用了20s，这座桥的长度是多少m？
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单项选择题

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.

Which of the following does the writer explain

A．Neurotoxins.

B．Microscopic organisms.

C．Predators.

D．Fish walks.
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