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: 'adult standing under red umbrella next to railing on walkway near water'. Reverse all words of length '8' in the given sentence.

adult gnidnats under red allerbmu next to railing on walkway near water