Medical research has shown that the widespread of use of cigarettes contributes ______the increase of cancers.

A．are shared by the stockholders
B．are all given to the policyholders as stocks
C．are used to reduce future insurance cost
D．are used in some investment

A．cook the same food in different ways
B．like the same kinds of food
C．have the same ideas about foods
D．know how to prepare the same food