■ pay 与 payment

payment 是付款的行为，或是一次交付的款额。

• The goods will be delivered on payment of the outstanding charges.一俟未清款项付清，当即送货。

pay 则指工资、酬金。

• starting pay起薪
• a holiday with pay工资照发的休假
• to work at very low (good) pay做工资很低（很高）的工作。

• one in
• one in 与 one out of
• one of
• one out of
• one-sided
• one 与 a
• on high
• on life support
• only
• only
• only
• only 与 alone
• on the air
• on the air...
• on the part of
• open
• open 与 close
• opportunity
• oppose
• oppose 与 be opposed to
• opposing
• optimistic
• -or
• or
• order