a)set somebody/something on somebodyATTACK to make people or animalsattack someone 使某人[动物]攻击某人
The farmer threatened to set his dogs on us.
那农民威胁说要放狗来咬我们。
b)if you are set on by people or animals, you are suddenly attacked by them 突然袭击
A thirty-five-year-old man was set on by four youths last night.
一名35岁男子昨晚突然遭到四个年轻人袭击。
nGrammar
Set on is usually passive in this meaning.
c)set somebody on/onto somebody to give someone information about a person who you think has done something wrong, because you want that person to be found and caught 向某人告发某人
2DETERMINEDdetermined about something 一心想/决心要/坚决反对(做)某事
Nina’s set on going to the party.
尼娜铁了心要去参加这次派对。
The government’s dead set (=completely determined) against the plan.
政府坚决反对这个计划。
Examples from the Corpus
set on/upon/against (doing) something• Lance Rees was set on as he passed the sorting office in Withernsea, Humberside, on his way to school.• Manuel Perez's brother left after his house was set on fire.• They were hacked to death and their bodies set on fire.• Time limits may be set on how long employees can leave their goods in storage and receive reimbursement from their employers.• Once again I detect a falseopposition: an idealisedrealityset against the alien forces of darkness.• A pail of cold water for washing was set on the floor so that performers had to bend over to use it.• Margarett set upon the package, tearing at its wrappings, only to find beneath it another carton, then still another.• Were the limits set on their radiationexposureacceptable?