easy用作副词的疑问（be easy caught up-2017浙江卷）

下面的段落摘自2017 年高考考试英语的浙江卷读后续写：

Mac was pedaling hard now. He waved and yelled at passing cars but was careful not to slow down. He saw a steep uphill climb before him. He knew that once he hit the hill, he’d be easy caught up and the wolf’s teeth would be tearing into his flesh.

对划线部分的 be easy caught up 有疑问，为何不需要 easily？虽然 easy 也可以用作副词，但书上说，它的副词使用方法是非常有限的，能如此用吗？

easy用作方法状语为非正式语体，词典将这种使用方法归为副词。改为easily更为容易见到。