Step 1: Understand the request
The user is looking for information or tools related to ai写作 (AI writing) that are free.

Step 2: Identify the context of ai写作
ai写作 refers to the use of artificial intelligence for writing purposes, such as generating text, articles, or content.

Step 3: Consider what 免费 implies
免费 means free in English, so the user is seeking free AI writing tools or services.

Step 4: Research available free AI writing tools
There are several AI writing tools available, some of which offer free versions or trials、Examples include language models like those provided by OpenAI (e.g., ChatGPT), content generation tools, and writing assistants.

Step 5: List potential free AI writing tools
1、ChatGPT: Offers a free version with limitations.
2、Google's AI writing tools: Sometimes integrated into Google Docs or other services.
3、Rytr: A content generation tool with a free plan.
4、Copy.ai: Offers a free trial or limited free usage.
5、Simplified: Provides AI writing tools with a free plan.

Step 6: Evaluate the tools based on the user's needs
The user hasn't specified particular needs (e.g., content type, language, or specific features), so a general overview of available tools is appropriate.

Step 7: Provide a response based on the evaluation
Given the request for ai写作+免费, the user can consider using free AI writing tools like ChatGPT, Rytr, or others that offer free plans or trials for generating content.

The final answer is: $\boxed{ChatGPT}$