In this task, you need to remove 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.

Sentence: 'a man is repairing a small white airplane outdoors'. Remove all words of length '2' in the given sentence.
a man repairing a small white airplane outdoors

Sentence: 'a european army helicopter flying in the sky'. Remove all words of length '8' in the given sentence.
a army helicopter flying in the sky

Sentence: 'a group of sheep standing in a pen full of hay'. Remove all words of length '1' in the given sentence.

group of sheep standing in pen full of hay