第五次Revert "第四次 dd.txt"

This reverts commit 51445793914920e881f45bec84905ed144b18c46.
換master啦
rebase啦
s2第一次s2-1.txt
在mater改，在slave2commit
新增x2.txt
x6
x7
Revert "x7"

This reverts commit 8f1e155c91c63ead1741f7285cfea7088b2e8a73.