annul all outdated rules
废除一切陈规
annul a subcontract
废除分包合同
annul the drug’s effect
使药失去疗效
annul a visa already issued
宣布签证作废
annul the tendering process
取消招标
annul a letter of credit
取消信用证
negate the present with the ancient
以古非今
negate decimal with extend
非扩展十进制