Many "Type 'std::string' could not be resolved"

My project works fine some days ago. But one day, some errors come out without modifying code.

There are too many “could not be resolved” error.

Both eclipse 4.2 and eclipse 3.7 have the same problem.
android-ndk-r8c
cocos2d-1.0.1-x-0.13.0-beta
Win 7 + Cygwin

There is a strange phenomenon。
If I delete the project and reimport the project, there is no error, and build success. But if I open one file of the project before build, complie errors come out,build will fail.

Is there anybody can help me?

change to eclipse 3.6.2, works ok