he (mustn't- shouldn'y) climb the tree it's dangerous

mustn't

(( strong advice))

Aha I agree Wth you .
The Answer is mustn't

the answer

must not

both of them are correct

should is used to express advice
but must is used to express strong advice
so i think the answer is must because of the word dangerous

Good luck.
Mr . atef abu bakr
Teacher of English
Somosta secondary institute for boys

should is used to express advice

but must is used to express strong advice

so

I think the answer is must because of the word dangerous

sorry, i don't agree with u
the answer is shouldn't
mustn't is used to express prohibition not strong advice
so it means it is illegal or not allowed

"Mustn't " is completely right