Allowed fits in the first blank while aloud is appropriate for the second blank; I presume you are inquiring about homophones, correct?
Answer:
Permission modal: Students are permitted to utilize their laptops during class to take notes and access e-books.
Obligation modal: Both students and teachers must engage in paper recycling.
Prohibition modal: It is not necessary for the school to keep the lights on when the classroom is unoccupied
Explanation:
Modals conveying permission serve to express whether an action can be performed or to seek confirmation regarding it. The modals can, may, and could are included in this category, with may and could being more formal choices compared to can.
Obligation modals highlight something that is mandatory. Must is associated with personal requirements such as I must prepare for the exam, or rules like you must wear gloves in the lab. On the other hand, have to indicates a broader obligation, like Students have to prepare diligently for the exam.
Prohibition modals feature in sentences that denote actions that are forbidden. Terms such as cannot and must not convey these restrictions. For instance, smoking is not allowed inside this building.
