Complete the employee's warning message about the new workplace rules. Choose the correct phrase to fill in the blank.

The boss explicitly warned us ________ the office fern espresso, no matter how droopy it looks.

The correct answer is not to feed.

To report a negative command or request (e.g., "Don't feed the plant!"), we use a reporting verb (like warned, told, or asked) followed by an object ("us") and not to + infinitive ("not to feed").