请教新概念英语二册73课中两个读音问题

请教新概念英语二册73课中两个读音问题在英语中No one noticed the boy as he crept off. From there本句中的as是不是可以不发音,直接略过去.He has surely set up a record for the thousands of children who dream of evading school.本句中的of发什么音. 谢谢!