When the airplane takes off ， the passengers are told to _______ their seat belts.

Which of the following statements is supported in this passage（） A: 50% of the US population forgot to wear safety belt every day. B: The first safety belts in cars appeared forty years ago. C: Safety belts "trap" people in cars that are burning or sinking in water. D: Not wearing safety belts will be fined.

Since ________ all cars sold in ________ have been equipped with seat belts.

For your safety, please go back to your seat and the seat belts.

Unfortunately belts are worn only by ________ percent of drivers and passengers in cities.

Seat belts: remain -1- while the “Fasten seatbelts” sign is on

Passengers must fasten their seat belts during take-off or landing.

Before the flight takes off, all the passengers are asked to (fast) ______ their seat belts.

Passengers ______ to fasten their belts. A: ask B: will ask C: to ask D: are asked

中国大学MOOC: All the passengers _____ board the plane should fasten their seat belts.