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 dog lays next to a bag on a couch'. Reverse all words of length '4' in the given sentence.
Example Output: a dog syal txen to a bag on a couch

Example Input: Sentence: 'a large bird stands on the ledge of a window'. Reverse all words of length '3' in the given sentence.
Example Output: a large bird stands on eht ledge of a window

Example Input: Sentence: 'a horse standing in front of a barn'. Reverse all words of length '1' in the given sentence.
Example Output:
a horse standing in front of a barn