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: 'two giraffes are standing in some tall dry grass and trees'. Reverse all words of length '3' in the given sentence.

owt giraffes era standing in some tall yrd grass dna trees