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 is a group of people standing on the beach'. Reverse all words of length '8' in the given sentence.
Example Output: there is a group of people gnidnats on the beach

Example Input: Sentence: 'a frosty car hood shows with a stop sign'. Reverse all words of length '5' in the given sentence.
Example Output: a frosty car hood swohs with a stop sign

Example Input: Sentence: 'a girl is sitting on a bus with her knees up'. Reverse all words of length '1' in the given sentence.
Example Output:
a girl is sitting on a bus with her knees up