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 group of skiers standing at the base of a mountain'. Reverse all words of length '3' in the given sentence.

Answer: a group of skiers standing at eht base of a mountain


Question: Sentence: 'two men in baseball uniforms running across a field'. Reverse all words of length '7' in the given sentence.

Answer: two men in baseball uniforms gninnur across a field


Question: Sentence: 'a flock of pigeons standing around a rock and gravel area'. Reverse all words of length '1' in the given sentence.

Answer:
a flock of pigeons standing around a rock and gravel area