The teacher tells her students, who promise they will study quietly for three hours, that she won't give extra assignments.
Explanation:
According to the rest of the sentence, grammatically, "will study" is the correct answer because the teacher tells her students that she won't give extra assignmentes, and the students promise they will be quiet for that reason, given the context, they would probably be studying.
Viktor Petrovich Bryukhanov (Ukrainian: Віктор Петрович Брюханов, Russian: Виктор Петрович Брюханов) was the director of the Soviet Central Committee on nuclear energy in 1986.
According to the doctrine of separation of powers, the U.S. Constitution distributed the power of the federal government among these three branches, and built a system of checks and balances to ensure that no one branch could become too powerful.
