required

"Although he was unused to the situation, he tried to act naturally."

"He is a student of life."

"My friend told me there was something in the box, but I didn't know what it was yet. "

"The mandatory for the game requires the players to keep the disc above the painted line. "

"Attendance at the meeting is required."

"This flow chart represents the assignment of tasks in our committee."

"an obligatory promise"

"The complete survey was handed in to the teacher. "

"The school's new addition includes a modern necessary. "

"Access to clean water is an indispensable for human survival. "

"Students need to buy their textbooks before the first day of class. "

"The teacher spoke authoritatively about the importance of studying, and the students listened attentively because they trusted her knowledge. "