A video has been released of the kidnapped girls in Nigeria

Here is the latest story from the BBC about the 300 kidnapped Nigerian girls:

http://www.bbc.com/news/world-africa-27373287

Vocabulary to help you understand the article (this article is pretty simply written):

to be kidnapped - to be taken against one's will and held, usually until money is paid for one's release. Apparently these girls were taken by this group to try to force the Nigerian government to release other members of this group from jail.  

Boko Haram - the name of the group that kidnapped the girls. The name means: "Western education is sinful" - sinful means against the will of God or against God's law

a hijab - a type of Muslim clothing for women

converted - switched, changed, transitioned into

abducted - taken by force (it always pertains to taking a human being)

threatened to sell them - they threatened to sell the girls as slaves

liberated them - freed them; the group is claiming they have freed the girls from a 'wrong' religion and helped them accept the 'true' religion

correspondents - journalists

to avoid detection - to make sure they are not found