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 large elephant standing in the wild'. Reverse all words of length '5' in the given sentence.
Example Output: a egral elephant standing in the wild

Example Input: Sentence: 'two giraffes are walking through a field of prairie grass'. Reverse all words of length '1' in the given sentence.
Example Output: two giraffes are walking through a field of prairie grass

Example Input: Sentence: 'group of people in a truck observing elephants'. Reverse all words of length '9' in the given sentence.
Example Output:
group of people in a truck gnivresbo stnahpele