Help the party planners keep everything a secret for their suspicious friend. Select ALL the statements that correctly complete their checklist using the passive voice with modals.
The correct answers are The cake will be delivered to the back door and The balloons might be seen if we put them by the window.
The correct structure is modal + be + past participle (e.g., will be delivered, might be seen).
"The invitations must be send out tonight" is incorrect because "send" is the base form, not the past participle (must be sent).
"The music should kept..." is incorrect because it is missing the verb "be" (should be kept).