名詞 second hand:

1. an intermediate person; used in the phrase `at second hand'
2. hand marking seconds on a timepiece

形容詞 second hand:

1. derived from what is primary or original; not firsthand
   同義詞：secondhand
2. previously used or owned by another
   同義詞：secondhand, used

副詞 second hand:

1. from a source of previously owned goods
2. by indirect means
   同義詞：secondhand

1. I only heard the news at second hand.
   我只是間接聽到這個消息的。
2. Most of our knowledge is at second hand.
   我們的大部分知識是間接的。
3. He sold a bundle of old magazines to the second hand bookstore.
   他把一捆就雜志賣給了舊書店。
4. He bought a second hand bike good for80 yuan.
   他買了一輛值80元的二手自行車。