Can somebody paraphrase this for me? doctors believe smoking causes lung cancer by damaging the cells that line the lungs. when you inhale cigarette smoke, which is full of cancer-causing substances (carcinogens), changes in the lung tissue begin almost immediately.

Doctors believe that when you inhale smoke, it can cause lung cancer because it damages the cells inside of your lungs. Smoke is filled with carcinogens, which are cancer causing substances. These changes in lung tissue can begin almost immediately.

Hope this helps :)