add by baiziying
lihai
by lihai Merge https://github.com/pinguo-baiziying/lession1 into baiziying-master

Conflicts:
	lession.txt
lihai
Merge https://github.com/pinguo-liuhongwei/lession1 into lhw

Conflicts:
	lession.txt
Merge https://github.com/pinguo-liuhongwei/lession1 into lhw

Conflicts:
	lession.txt
Merge https://github.com/pinguo-liuhongwei/lession1 into lhw
Merge pull request #24 from pinguo-lihai/master

lihai fourth
well done