名人教英文：yet的多种用法
yet 这个字看似浅易，其实有许多意思和用法。最常见的是在完成时态（perfect tense）的否定句中表示「仍然（未）」，例如：mr chan has not arrived yet / mr chan has not yet arrived.
yet 间或用于其他时态的句子，例如：i cannot leave the hospital yet. the doctor has told me to stay for two more days.
still 一样译作「仍然」、「还是」，但意思及用法和 yet 有分别。yet 表示说话者期望要发生的事情还未发生，而 still 则表示事态仍然持续，如：we are still waiting for mr chan.
have yet to do something 虽然在句法上是肯定句，但含有否定的意思，表示应做而仍未做，例如：
‧ peter has yet to complete the project.
‧the police has yet to find out the cause of the traffic accident.
此外，yet 可用于肯定语气的句子，例如 may/ might/ can/ could yet 表示依然有可能，例如：don't give up! our team may yet win the competition.
yet 还可以解作「到目前（或当时）为止（最……的）」：the harry potter series is j k rowling's most popular work yet.
yet another/more/ again 有「又」、「再」的意思：
‧ that tennis player lost yet another match.
‧the passengers will face yet more flight delays because of the bad weather.
‧ sam failed the driving test yet again.
yet 亦是连接词，和 but 近义，例如：he lives near the school, yet he is always late. 因为 yet 本身已经有「不过」的意思，所以不能和 but、however 等字一同使用。
这个字又可以修饰将来的事态，表示「由现在起的某个时段」，例如：
‧miss lee won't be back for a few weeks yet.
‧the strike (罢工) will probably go on for some time yet.
要注意的是：虽然yet有多种用法，但 mr chan has arrived yet 肯定不对。完成时态的肯定句不用 yet，只能用 already（已经）：mr chan has arrived already.