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: 'a man walking a brown horse down a race track'. Reverse all words of length '4' in the given sentence.
Example Output: a man walking a brown horse nwod a ecar track

Example Input: Sentence: 'a grey cat with green eyes looking straight ahead'. Reverse all words of length '1' in the given sentence.
Example Output: a grey cat with green eyes looking straight ahead

Example Input: Sentence: 'a bunch of apples hanging from a green tree'. Reverse all words of length '2' in the given sentence.
Example Output:
a bunch fo apples hanging from a green tree