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.

Example Input: Sentence: 'there are many animals standing on the top of this mountain'. Reverse all words of length '4' in the given sentence.
Example Output: there are ynam animals standing on the top of siht mountain

Example Input: Sentence: 'a herd of zebra standing in a forest'. Reverse all words of length '1' in the given sentence.
Example Output: a herd of zebra standing in a forest

Example Input: Sentence: 'a man rides his chopped motorcycle down the street at a motorcycle rally'. Reverse all words of length '5' in the given sentence.
Example Output:
a man sedir his chopped motorcycle down the street at a motorcycle yllar