Fill in the blank with the correct preposition.
It is dangerous to enter __________the prohibited zone.

into

The correct preposition to fill in the blank is into. The preposition into is used to indicate movement or placement inside something. In this case, it is dangerous to enter into the prohibited zone, which means that it is dangerous to go inside the prohibited zone.

The other options are incorrect.

• In can also be used to indicate location or position, but it is not the most appropriate preposition to use in this case.
• On is used to indicate movement or placement above something.
• By is used to indicate association or cooperation.