英语翻译Only for explanatory purposes it is possible to conceive

英语翻译
Only for explanatory purposes it is possible to conceive a hypothetical observer and trajectory on which the proper time of the clock would coincide with coordinate time:such an observer and clock have to be conceived at rest with respect to the chosen reference frame v=0 in equation (2) above) but also (in an unattainably hypothetical situation) infinitely far away from its gravitational masses (also U=0 in equation (2) above).[5] Even such an illustration is of limited use because the coordinate time is defined everywhere in the reference frame,while the hypothetical observer and clock chosen to illustrate it has only a limited choice of trajectory.
A coordinate time scale (or coordinate time standard) is a time standard designed for use as the time coordinate in calculations that need to take account of relativistic effects.The choice of a time coordinate implies the choice of an entire frame of reference.
As described above,a time coordinate can to a limited extent be illustrated by the proper time of a clock that is notionally infinitely far away from the objects of interest and at rest with respect to the chosen reference frame.This notional clock,because it is outside all gravity wells,is not influenced by gravitational time dilation.The proper time of objects within a gravity well will pass more slowly than the coordinate time even when they are at rest with respect to the coordinate reference frame.Gravitational as well as motional time dilation must be considered for each object of interest,and the effects are functions of the velocity relative to the reference frame and of the gravitational potential as indicated in equation (2) above.

这个人表达能力有问题.不要看他的.换个东西看.