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 sleeping in bed with a cat lying on him'. Remove all words of length '5' in the given sentence.
a man sleeping in bed with a cat on him

Sentence: 'a brown bear is standing at the base of the tree'. Remove all words of length '3' in the given sentence.
a brown bear is standing at base of tree

Sentence: 'a person is skiing down a steep slope'. Remove all words of length '6' in the given sentence.

a is down a steep slope