Please tell him about the picnic.(改为否定句)

Please tell him about the picnic.(改为否定句)
Please tell him about the picnic.(改为否定句)

Please tell him about the picnic.(改为否定句)
Please don`t tell him about the picnic

Don't tell him about the picnic,please.

Please don't tell him about the picnic.
原句就是祈使句，直接加don't就可以了

Please don’please tell me about the picnic..