a nonmetallic bivalent element that is normally a colorless odorless tasteless nonflammable diatomic gas; constitutes 21 percent of the atmosphere by volume; the most abundant element in the earth's crust
the 15th letter of the Roman alphabet
the blood group whose red cells carry neither the A nor B antigens;
"people with type O blood are universal donors"
He didn't know that was Bical O's conspiracy. 完全不知到这是邪恶二齿猪的阴谋啊！
More flowers will come to you with perfume and pride,O world! 啊，世界，更多的花涌到你的怀里，带着芬芳，带着骄傲！