noun
1
BAD : To get a job in Switzerland, foreigners need a special permission.
GOOD : To get a job in Switzerland, foreigners need special permission.
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Permission is an uncountable noun: 'If you want to put up a tent, you'll have to get the farmer's permission.' 'Nobody is allowed to leave early without permission.'
2
BAD : Eventually he gave me the permission to stay at home.
GOOD : Eventually he gave me his permission to stay at home.
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(their/his mother's/the headmaster's) permission but NOT the permission : 'I'm sure that they'll let you use the library but it's better to have official permission.'