The primary research shows that the evolution process of requirements can be regarded as normal when the requirements evolutionary process changing chart is consistent with the model trajectory.
初步研究表明，只要需求演化过程的变化图和模型的轨迹图一致，那么需求的演化过程就可以看成是正常的。
2
The long run generally brings greater contentment, according to studies that chart the trajectory of happiness over a life span.