Update my answer to Exercise 1.33.

The following 2 files have been modified:

	Exercise_1.33.pdf
	Exercise_1.33.tm

The implementation and test for this exercise are located in the following
2 newly added files:

	Exercise_1.33.scm
	Test_for_Exercise_1.33.scm

Thank you!
							Lawrence R. Amlord
							   May 10th, 2013
							   Xi'an, China