extemporaneous
adj.
"made, done, procured, or furnished 'at the time,'" hence "unpremeditated," 1650s, from Medieval Latin extemporaneus, from Latin ex tempore (see extempore). Earlier was extemporal (1560s); extemporanean (1620s). Related: Extemporaneously; extemporaneousness.
〔蒋〕[tempor=time时，-aneous形容词后缀，…的] 临时的，当场的，无准备的