3 sentences for 买卖 (mǎi​mài — trade)

1. 买卖军用武器是违法的。

   mǎi​mài jūn​yòng wǔ​qì shì wéi​fǎ de.

   It's against the law to buy or sell military weapons.

   Source: OpenSubtitles

2. 买卖双方通过中间人达成了协议。

   mǎi​mài shuāng​fāng tōng​guò zhōng​jiān​rén dá​chéng le xié​yì.

   The buyer and seller reached an agreement through a middleman.

   Source: Dong Chinese Dictionary

3. 这些资产全归官有，私人不能随意买卖。

   zhè​xiē zī​chǎn quán guī guān yǒu, sī​rén bù néng suí​yì mǎi​mài.

   These assets are all state-owned; private individuals cannot buy or sell them at will.

   Source: Dong Chinese Dictionary