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.

[Q]: Sentence: 'a small white dog with a hat on his rear end'. Reverse all words of length '3' in the given sentence.
[A]: a small white god with a tah on sih rear dne


[Q]: Sentence: 'a hand reaching out towards a standing giraffe'. Reverse all words of length '7' in the given sentence.
[A]: a hand reaching out sdrawot a standing effarig


[Q]: Sentence: 'a train engine is pulling freight cars on the tracks'. Reverse all words of length '4' in the given sentence.
[A]:
a train engine is pulling freight srac on the tracks