Lung cancer is the No.1 cancer to kill American people. No cancer kills more American than lung cancer.

A. 对
B. 错

How do doctors test for a lung cancer?

A. a high-tech screening test
B. routine blood test
C. routine urine test
D. routine physical examination

How do doctor screen a heavy smoker for a lung cancer?

A. These heavy smokers have been screened with chest X-ray.
B. These heavy smokers have been screened with CT scan.

Why do doctors always suggest their patients to take the lung cancer screening test earlier?