Definition: In this task, you need to reverse all words of a given length in the sentence. The number of letters in a word determine its length. For example, the length of the word "apple" is 5.
Input: Sentence: 'a bear with blackbrown fur from front facing and looking into camera with green grass in mouth standing in grass rocks and bushes outside'. Reverse all words of length '8' in the given sentence.

a bear with blackbrown fur from front facing and looking into camera with green grass in mouth gnidnats in grass rocks and bushes outside