update readme

README.md

@@ -16,17 +16,18 @@ moon phases uses [VSOP87](ftp://ftp.imcce.fr/pub/ephem/planets/vsop87) planetary
 theory and [LEA-406][] lunar theory.
 
 The full version of LEA-406 and VSOP87 are used by default. A truncated version
-, aa.py, is also included. The full version is slightly slower than the
-truncated version. Their accuracy of finding apparent Sun and Moon longitude
-compare to the DE431 based JPL Horizon are showed in following figures.
+, aa.py, which is slightly faster, is also included. The accuracy of this
+implementation, when compare to the apparent Sun and Moon longitude finded by
+the DE431 based JPL Horizon, are showed in following figures:
 
 ![aa_full][]
 ![aa_trunc][]
 
-For the time span from 1949 to 2100, lunar calendar created by above algorithm
-has only two discrepancies compare to the HKO's version: one is a solar term on
-1979-01-20, the other is a new moon on 2057-09-29. It is caused by few seconds
-of error happens around midnight(UTC +8).
+The lunar calendar generated by the full and truncated version is identical for
+the period 1949 - 2100.  There are only two discrepancies compare to the HKO's
+version: one is a solar term on 1979-01-20, the other is a new moon on
+2057-09-29. It is caused by few seconds of error happens around midnight(UTC
++8).
 
 The official timezone before 1949 is slightly different than the current UTC +8
 therefor the computed lunar calendar may not represent history accurately.
@@ -35,7 +36,7 @@ therefor the computed lunar calendar may not represent history accurately.
 ### License
 
 This package is released under the terms and conditions of the BSD License, a
-copy of which is include in the file COPYRIGHT.
+copy is include in the file COPYRIGHT.
 
 **Hong Kong Observatory** has been very kind to provide and grant the permission
 of using their conversion table, which is only for Non-Commercial use.