fix ex9.40
Revert "fix ex9.40"

This reverts commit f3701e318e53705887b973afd2e39305182d1255.
fix ex9.40
Revert "fix ex9.40"

This reverts commit b7783bebd6c0a60175abacacf5c688f762392739.
fix 9.40
fix ex11.34
Merge pull request #107 from shidenggui/master

fix 9.40