Meaning of AFRAID in English
BAD : The road to the airport was very busy and we were afraid to miss the plane.
GOOD : The road to the airport was very busy and we were afraid of missing the plane.
be afraid to do sth = be unwilling to do something because you are frightened about what may happen: 'She was afraid to eat it in case it was poisonous.' 'Don't be afraid to ask for help.'
be afraid of doing sth = be worried or anxious about something which might happen: 'Most criminals are afraid of being caught.' 'He says that he is afraid of losing his job.'
Longman Common Errors English vocabulary. Английский словарь распространенных ошибок Longman. 2012