于正是中国大陆知名的编剧、导演，他的作品多次获得观众的喜爱和认可。然而，近期有关于于正为何不签赵丽颖的问题引起了广泛的关注和讨论。为了解决这个疑问，我们需要从多个方面来探讨。

Firstly, it is important to note that the decision of signing an actor or actress for a project ultimately rests on the director's judgement. As a director, Yu Zheng has his own artistic vision and preferences when it comes to casting. It is possible that he believes other actresses better suit the characters he envisions for his works. Each director has their own unique style and creative ideas, and they often seek actors who can bring their characters to life in the most convincing way.

首先，需要注意的是，签约一个演员角色对于一个项目来说最终要由导演来决定。作为一名导演，于正在选择角色时有自己的艺术眼光和偏好。他可能认为其他女演员更适合他所设想的角色。每个导演都有自己独特的风格和创意想法，他们通常会寻找那些能够最真实地演绎角色的演员。

Secondly, contractual obligations and scheduling conflicts could also be factors contributing to the decision. Both Yu Zheng and Zhao Liying may have their own commitments and limitations which make it difficult for them to collaborate on a project. Actors often have busy schedules and may already be committed to other projects or endorsements, making it challenging for directors to secure their participation. These logistical considerations can greatly impact casting decisions.

其次，合约义务和时间冲突也可能是影响这个决定的因素。于正和赵丽颖可能都有各自的承诺和限制，这使得他们很难在一个项目上合作。演员通常时间紧张，可能已经承诺参与其他项目或代言，这使得导演很难确定他们的参与。这些日程安排的考虑可以极大地影响角色选择。

Furthermore, artistic differences and personal relationships may also play a role in this situation. It is possible that Yu Zheng and Zhao Liying have different creative visions or preferences, which can lead to a decision not to work together. Additionally, personal relationships and dynamics within the entertainment industry can sometimes influence casting decisions. It is important to remember that the entertainment industry is complex and multifaceted, and there are often many factors at play behind the scenes.

此外，艺术理念和个人关系也可能在这个情况下起着作用。于正和赵丽颖可能有不同的创意或偏好，这可能导致他们不愿意合作。此外，演艺圈内的个人关系和力量对于角色选择也可能产生影响。需要记住的是，娱乐行业是复杂多变的，背后往往涉及各种因素。

In conclusion, the decision of why Yu Zheng has not signed Zhao Liying for a project can be attributed to a combination of artistic vision, contractual obligations, scheduling conflicts, personal relationships, and industry dynamics. As outsiders, we can only speculate on the reasons behind this decision, but it is important to recognize that casting decisions in the entertainment industry are often complex and multifaceted.

总结起来，于正为何不签赵丽颖可能是由于艺术视野、合约义务、时间冲突、个人关系以及行业动态等多种因素的综合作用。作为外部人士，我们只能对这个决定的原因进行猜测，但我们要认识到，娱乐行业中的角色选择往往是复杂多元的。

English translation:

于正为什么不签赵丽颖 (Why Yu Zheng doesn't sign Zhao Liying)

Yu Zheng is a well-known screenwriter and director in mainland China, and his works have been loved and recognized by the audience. However, recently there has been widespread attention and discussion about why Yu Zheng doesn't sign Zhao Liying. To solve this question, we need to explore from multiple aspects.

Firstly, it is important to note that the decision of signing an actor or actress for a project ultimately rests on the director's judgment. As a director, Yu Zheng has his own artistic vision and preferences when it comes to casting. It is possible that he believes other actresses better suit the characters he envisions for his works. Each director has their own unique style and creative ideas, and they often seek actors who can bring their characters to life in the most convincing way.

Secondly, contractual obligations and scheduling conflicts could also be factors contributing to the decision. Both Yu Zheng and Zhao Liying may have their own commitments and limitations which make it difficult for them to collaborate on a project. Actors often have busy schedules and may already be committed to other projects or endorsements, making it challenging for directors to secure their participation. These logistical considerations can greatly impact casting decisions.

Furthermore, artistic differences and personal relationships may also play a role in this situation. It is possible that Yu Zheng and Zhao Liying have different creative visions or preferences, which can lead to a decision not to work together. Additionally, personal relationships and dynamics within the entertainment industry can sometimes influence casting decisions. It is important to remember that the entertainment industry is complex and multifaceted, and there are often many factors at play behind the scenes.

In conclusion, the decision of why Yu Zheng has not signed Zhao Liying for a project can be attributed to a combination of artistic vision, contractual obligations, scheduling conflicts, personal relationships, and industry dynamics. As outsiders, we can only speculate on the reasons behind this decision, but it is important to recognize that casting decisions in the entertainment industry are often complex and multifaceted.