It is required that passengers remain ________ when the plane is taking off or landing.
#18805
A
sit
B
seating
C
sat
D
seated
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Mary kept weighing herself to see how much _______ she was getting.
#20428
A
heavier
B
heavy
C
the heavier
D
the heaviest
I really appreciate that your help is of great _________. 
#19778
A
useful
B
value
C
important
D
worth
People who often stay up late are _________ to suffer from heart attacks than those  who are not.
#18231
A
six times more likely
B
as likely six times
C
six times as likely
D
more likely six times