Она вероятно не увидела его в толпе

Она вероятно не увидела его в толпе и поэтому не ответила на его приветствие

Результаты (английский) 1:

She probably did not see him in the crowd and therefore had not responded to his greetings

Результаты (английский) 2:

She probably did not see him in the crowd and so did not respond to his greeting

Результаты (английский) 3:

she probably wouldn't see him in the crowd and so had not responded to his greeting