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 river filled with lots of boats and surrounded by buildings'. Reverse all words of length '4' in the given sentence.
Example Output: a river filled htiw stol of boats and surrounded by buildings

Example Input: Sentence: 'a cat sleeping with is hear resting on a keyboard'. Reverse all words of length '4' in the given sentence.
Example Output: a cat sleeping htiw is raeh resting on a keyboard

Example Input: Sentence: 'a toilet sitting the grass next to a road'. Reverse all words of length '2' in the given sentence.
Example Output:
a toilet sitting the grass next ot a road