Question

Because cellular telephones emit signals that can interfere with cockpit-to-control-tower transmissions, airplane passengers’ use of these instruments at all times that the airplane is in motion, even while on the ground, are prohibited.
(A) at all times that the airplane is in motion, even while on the ground, are
(B) at all times during which the airplane, even while on the ground, is in motion, are
(C) during airplane motion, even when it is on the ground, are
(D) during times of the airplane being in motion, even on the ground, is
(E) when the airplane is in motion, even while on the ground, is

Answer 1

The correct syntax and grammar for this sentence is E: "Because cellular telephones emit signals that can interfere with cockpit-to-control-tower transmissions, airplane passengers’ use of these instruments when the airplane is in motion, even while on the ground, is prohibited. "

The two changes made to the original sentence are:

• replacing "at all times that" by "when." The meaning of the original phrase (any time the airplane is moving) is conveyed just as well by the term "when," and its shortness makes the already long sentence less heavy
• replacing "are" by "is." Writing "are" was incorrect because the subject of this verb is a singular: "airplane passengers’ use."