Before revision: For example co-op 3d-design program can let multiple people design at same time, not support for guided help - tell the other guy what to do through markings and text, without talking to the person.
After revision: For example : Co-op 3d-design program can let multiple people design at same time, but does not have support for guided help - tell the other guy what to do through markings and text, without talking to the person.