Add my pratice on Chapter 4.

Included is the following file:

	Chapter_4.scm

Thank you!
							Lawrence R. Amlord
							   Aug 31st, 2013
							   Xi'an, China
Add my Practice to Chapter 5.

Included is the following file:

	Chapter_5.scm

Thank you!
							Lawrence R. Amlord
							   Aug 31st, 2013
							   Xi'an, China
Add my practice on Chapter 6.

Included is the following file:

	Chapter_6.scm

Thank you!
							Lawrence R. Amlord
							   Sept 1st, 2013
							   Xi'an, China
Add my practice on Chapter 7.

Included is the following file:

	Chapter_7.scm

Thank you!
							Lawrence R. Amlord
							   Sept 1st, 2013
							   Xi'an, China