About
HSK levels

    zài

    1. again; once more; re-
    2. further; beyond this point of time
    3. (before an adjective) more
    4. then (after sth, and not until then)
    5. no matter how ... (followed by an adjective or verb, and then (usually) 也[ye3] or 都[dou1] for emphasis)
    6. (used to introduce additional information, as in 再則|再则[zai4 ze2], 再就是[zai4 jiu4 shi4] etc)
    7. (literary) to reappear; to reoccur

    请再说一遍。 Qǐng zài shuō yī biàn.