Why the rebels are called Freedom fighters in Libya ,but are called terrorist's in Afghanistan,Etc?

Depends on whether you support them or not. The Afghanistan rebels are not supported by the West because they foment anti-Western terrorism, they are ociated with a minority faction, they subjugate their women and impose a regime denying people religious freedom. The rebels in Libya are supported by the West as they are a popular inclusive movement, and they oppose a regime that imposes excessive taxation, and has also supported terrorism in the past.