Sunkcost refers to the cost that has been paid and cannot be recovered. Sunk cost is determined by the past decision or environment, and the cost caused by it cannot be changed by any decision now or in the future.
According to the above definition, which of the followings does not involve sunkcost?
Xiao Zhang is going to ask Xiao Li to go to the cinema. Because Xiao Li works overtime temporarily and can't refund her ticket, Xiao Zhang has to use the two movie tickets as a message