36. Why is headache a common disease in the USA?
=> Because every years about fifty million people have go to the doctor because of it.
37. What can people see when they have headaches?
=> They can see black dots or brights spots in front of their eyes.
38. Can people have pains on only one side of the head?
=> Yes they can.
39. When do people have headaches? 
=> They have headache when they work too hard or they are too nervous about something.
40. How can they prevent headaches?
=> They can prevent headaches by changing their diets or their lifestyle or simply by going to bed.

36. Why is headache a common disease in the USA?
=> Because every years about fifty million people have go to the doctor because of it.
37. What can people see when they have headaches?
=> They can see black dots or brights spots in front of their eyes.
38. Can people have pains on only one side of the head?
=> Yes they can.
 

39. When do people have headaches? 
=> They have headache when they work too hard or they are too nervous about something.
40. How can they prevent headaches?
=> They can prevent headaches by changing their diets or their lifestyle or simply by going to bed.