Definition: 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.
Input: Sentence: 'a child swinging at a tennis ball thrown by a man from across the net'. Remove all words of length '4' in the given sentence.

a child swinging at a tennis thrown by a man across the net