After briefing how ecological peril leads to ecological disaster and the cause of history, the paper analyses the ecological peril in terms of man-made causes and features in our country.

A dangerous mode in torsional vibration is found through a calculation of flexible degree of modality,then the weak links of this system are confirmed through a calculation of distributing rate of energy under this dangerous mode,it offers a theoretic evidence for the optimizing design of the drive system and shows an improved direction for the p.

Misunderstanding of the dangerous state and mixing up concrete and abstract potential damage offense hinder the development of theory of potential damage offense.

When there exists the dangerous state, even if the actor takes the positive measures to remove the dangerous state, there is also the accomplished form of dangerous offences.

Because it is different from defining the concept of potential in the civil-law crime and our continental criminal theory, so it is different to understand this problem when the dangerous state happened, the actor takes effective measures to prevent actual damage.

The general theories of criminal law show that the behavior of relieving the dangerous state automatically makes the crime accomplished.

In the dangerous crime,one who has caused the dangerous state and then eliminated it in order to prevent the damaging result,the theory and practice thought which wouldn\'t punished by penalty.