課本中不會教你的[U]693　upon/on demand和in demand

693　upon/on demand和in demand

① upon/on demand是“一經(jīng)請求即付”的意思。

② in demand是“有需要的，銷路好的”意思（badly wanted by a lot of people）。

Our goods are in great demand. 我們的貨物銷路很好。

The book about robots was much in demand. 那本關于機器人的書許多人都想看。