Fill in the blanks: A driver should always be mentally alert. He is likely to cause disaster if he indulges in _______.
Fill in the blanks: A driver should always be mentally alert. He is likely to cause disaster if he indulges in _______.
(A) a grey eminence
(B) hang up
(C) a brown study
(D) a mare’s nest
"A brown study" is an idiomatic way of describing someone deeply absorbed in thought, daydreaming, or being so engrossed in one's own thoughts that one becomes unaware of the outside world. In case of driving this type of inattentiveness and mental distraction without focus could be very dangerous and might lead to a calamity since a driver should at all times be mentally alert and attentive to the road.