jupyter，只读打开一个文件，名为file

Sorry, as an AI language model, I don't have access to the local file system to perform this task. However, I can provide you with the general steps to open a file in read-only mode in Jupyter Notebook.

1. Import the necessary libraries:

import io

2. Open the file in read-only mode using the `open()` function:

with io.open('file.txt', 'r', encoding='utf-8') as f:
    # Perform operations on the file

In the above example, the file named `file.txt` is opened in read-only mode with the `r` parameter. The `with` statement ensures that the file is automatically closed after the operations are performed.

You can replace `file.txt` with the name of your file and modify the encoding parameter according to your file's encoding.