2oح
2oʾʲôѧ
2OڻѧбʾԭӣͨڱʾѧʽеԭӸ2O-Աʾӡ...
ѧ2oʾʲô
2ԭӡݲѯԪڱʾOΪԪأֵʱOԭӣ2O2ԭӡ
2һ|0O˫ôд?
2468101214161820222426283032343638404244464850525456...
ڻѧ,2Oʲô???
ڻѧУ2Oԭ ԭ [yng yun z]oxygen atom ۵༭μ ԭӵԭӺ8ӣ...
2oح|ж?
ĩβ0ģݣǰλܱ4ģҲ꣬
2OO2ʲô?
2O2 ͬ 12O2λ 2O2 1λ Բͬ...
2OO2ʲô
2ͬ2O2λO2 1λ3Բͬ2OԭӷdzãȻв...
O22Oʲô?O2е2ʲô?
O2ָһ 2Oָԭ O22ָһкԭ 2O2ָԭ
2OӢô
twenty [ˈtwɛn(t)i] Ӣ [ˈtwɛnti]n. ʮʮꣻʮ num. ʮ adj. ʮ...