Once you have become _______ to cigarette smoking or alcohol, it is hard to _______it even though you try hard.
He knew nothing about the matter, but he talked as if he __it.
He ____ the cave before the police arrived, but he failed.
It was proved that the problem __ partly in the air pollution.
The cruel war __ his wife and children.
The boy seized a stick and ___ the dog, but it ran away.