1. Attractive people have more favorable personal attributes than unattractive people.
==> Attractive people may have more favorable personal attributes than unattractive people.
2. Economic sanctions are ineffective.
==> In some circumstances, economic sanctions are ineffective.
3. Alcohol causes people to become violent.
==> According to the studies, alcohols tend to make people to become violent.
4. Passive smoking causes cancer.
==> Certain types of cancer, passive smoking lead to cancer.
5. Recycling is the best solution to the waste disposal problem.
==> n the circumstances of eco-awareness, recycling may be a good solution to the waste disposal problem.
6. Physical exercise prevents depression.
==> It is widely accepted that physical exercise prevents depression.
7. Deep tunnels are safer and less vulnerable to earthquake shaking than are shallow tunnels.
==> It is now generally recognized that deep tunnels are safer and may less vulnerable to earthquake shaking than are shallow tunnels.
8. Private schools provide a better education than do public schools.
==>It seems that private schools could often provide a better education than do public schools.