People of different countries and regions, different nationalities and cultures have formed with solidarity an Olympic family, ______they have deepened understanding and enhanced friendship.
If there is an intruder _____the campus, students should be _____through an announcement, ______teachers should lock their classrooms to keep the children safe.
Leaders of the BRIC countries-----Brazil, Russia, India and China----_______their second summit on Friday. President Hu Jintao then returned home to help direct relief work ______the deadly earthquake in Qinhai.
. Lion: Want to have a fight, little dog?
Dog: No. I don’t want to fight an animal that is ______extinction(灭绝). My master told me that we should protect endangered animals.