1. air freight, enormous, greenhouse gases

e.g. Air freight is likely to produce more greenhouse gases than other modes of transportation.

2. exposed to abuse, behavioral problems

e.g. The children who are exposed to abuse or neglect in the home are likely to have behavioral problems.

3. population expansion, accumulation of waste, degrade

e.g. Population expansion is the main reason for the huge accumulation of waste, which takes decades to degrade.

4. stiff punishment, reduce crime, are fearful of doing sth., commit crimes, offender

e.g. It is suggested that stiff punishment is an effective method to reduce crime, as offenders are fearful of getting caught and less likely to commit crimes.