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.
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Question: Sentence: 'a green apple and knife on dark wooden stairs'. Reverse all words of length '3' in the given sentence.

Answer: a green apple dna knife on dark wooden stairs


Question: Sentence: 'three people with backpacks on skies moving up a hill'. Reverse all words of length '9' in the given sentence.

Answer: three people with skcapkcab on skies moving up a hill


Question: Sentence: 'a couple of sheep standing in a grass field'. Reverse all words of length '1' in the given sentence.

Answer:
a couple of sheep standing in a grass field