By introducing the system of testifying by concealment and analyzing the necessity and feasibility of the system in our country,the thesis puts forward some tentative ideas to the construction and security measures of this system so as to improve the system that the criminal witness s appearance in court.

In the construction of concealed works for important levee of the Yangtze river,a large amount of design and technical data was needed,and along with further construction,more and more data will be accumulated.

Based upon analysis of concealed project of civil engineering, from beforehand control,processing control and post-action control quality management concealed engineering is analyzed in detail in order to make practical and reliable scheme to ensure engineering quality.

It has been long time that the examination and evaluation of the concealed engineering works are made via some conventional methods, such as excavation and drill sampling.

The quality of hidden works is the key to determine the quality of electrical engineering.

This essay analyses the types and application of hiding movements in tennis and studies the problems existing in training.