1.   All the measures that I catalogued earlier will help to reduce vehicle emissions - the principal cause of bad air.

2.   Deficiencies in the local infrastructure were assumed to be the principal cause of community distress.

3.   Equipment problems were considered to be the principal cause of inaccurate measurements.

4.   He could not accept that the goal or end of a process, the final cause, was the principal cause.

5.   However it is also the principal cause of their weaknesses.

6.   Nor is it much concerned with exceptions to the rule that, to every effect, there is one principal cause.

7.   The principal cause of the problem, however, was fertilizer run-XXXX off, which contaminated groundwater and led to eutrophication of surface water.

8.   He used Pareto analysis to identify the principal cause as a loose loading arm.

9.   Beyond the surge in tourism, the boom on Broadway and the lure of a safer city, Lynn said, the principal cause is the strong economy.