• Scientists want to know whether global warming is caused by 21.
• Insulation may cause the Earth to 22.
• There are many 23.  on the global climate.
• The 24.  does not remain static.
• We cannot understand the global climate without understanding 25.  

• The single greatest threat to health is 32.

• Disturbing findings about men’s health

• the group who was at most risk of early death is 33.

Possible causes are:

• drinking too much alcohol;

• heavy smoking;

• 34.

• no adequate exercise.

Environmental factors affecting health:

• air or water pollution

• the threat of 35.  is most under-rated.

Personal control of one’s health:

• A well-funded education campaign will help enhance 36.

• and many illnesses could be prevented by 37.

• Do exercises for 38.  so you may find someone to join you.

• Make adequate 39.  prevent sports injury.

• Reduce injuries by using 40.  techniques.