Before the plane takes -------, passengers must ------------their seat belts.

The correct answer is D: "off, fasten." The phrase "takes off" refers to the moment when the plane lifts off the ground and begins its flight. It is a phrasal verb that is commonly used in aviation. Therefore, the first blank should be filled with "off" to complete the phrase "takes off." The second blank should be filled with a verb that means to secure one's seat belt. The only option that fits this requirement is "fasten." "Tighten" and "tight" (options A and C) both imply that the seat belt is already secured and needs to be made even more secure, which is not the case. "Tighter" (option B) is incorrect because it uses the comparative form of the adjective "tight" instead of the verb form "tighten." Therefore, the correct answer is "Before the plane takes off, passengers must fasten their seat belts."
Generative