git pull 出现问题

Question

我在使用 git 时遇到问题。

我分支了一个存储库并编写了一些代码。

我的朋友克隆了它，做了一些更改，然后 push --all 到服务器。

我现在想通过 pull 查看这些更改，但我收到以下消息：

You asked me to pull without telling me which branch you
want to merge with, and 'branch.branchName.merge' in
your configuration file does not tell me, either. Please
specify which branch you want to use on the command line and
try again (e.g. 'git pull <repository> <refspec>').
See git-pull(1) for details.

If you often merge with the same branch, you may want to
use something like the following in your configuration file:

    [branch "threshold"]
    remote = <nickname>
    merge = <remote-ref>

    [remote "<nickname>"]
    url = <url>
    fetch = <refspec>

See git-config(1) for details.

我在这里做错了什么？