He was so surprised at being discovered that he did not even try to run away.
这句话的主干是he was so surprised that he did not try(他感到如此惊讶以至于不想尝试)
at being discovered是修饰为什么事感到惊讶
even是强调作用
to run away是他不想尝试做的事
1这里画线句子要用being
be surprised at doing sth.对做某事感到惊讶,是固定词组
be discovered被动语态,意思是被别人发现
2这句话是什么从句
整个句子使用了so……that句型,是状语从句,表示结果