VirtualBox not Mount sharedFolder with window 7

[hoapq]

I want to share the folder between VirtualBox :
- I install Guest Addition of VirtualBox
- Set up SharedFolder in VirtualBox Setting

But when I mount the folder in Centos (Guest) with VirtualBox, it allways the help of mount command. Here is my command:

mount –t vboxsf D:/shared ~/Desktop/share

I check there is /usr/sbin/mount.vboxsf.

I dont know how to fix this problem