英汉词典

1. 着手做;从事;承担
    When you undertake a task or job, you start doing it and accept responsibility for it.

    e.g. She undertook the arduous task of monitoring the elections.
           她承担了监督选举的艰巨任务。

2. 承诺；保证；答应
    If you undertake to do something, you promise that you will do it.

undertake的解释

    e.g. He undertook to edit the text himself.
           他答应亲自编辑正文的内容。