Question

Change this sentence into indirect speech:-He said,"be aware, there is tigers behind you!"

Answer 1

He suggested to be aware and said there was a tiger behind him.

Answer 2

He told me to be aware as there was a tiger behind me.
                                or 
he said that I should be aware because the tiger is behind me.
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there can be two indirect sentences, u can choose any one.
hope my answer helped u :)