Definition: 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.
Input: Sentence: 'some of the catholic school children are lined up in single file before the microphone'. Reverse all words of length '4' in the given sentence.

emos of the catholic school children are lined up in single elif before the microphone