There’re 24 h____  in a day .
What’s his j____ ? He’s a teacher .
Don’t l____ to music in class .
Jackie Chan is a very s____  actor . He’s in many movies .
S _____  is the first day of a week .
My mother has lots of work to do every day . She’s very b____ 
Beijing is the capital （首都）of C____ .
I can’t a____  that question. It’s too difficult
Best w____ to you , Miss Jin . 
Kate , please w____  your name on the card .

下列化合物中均含有氮元素，若按氮元素的化合价由低到高的顺序排列：①NH₃；②N₂；③NO；④X；⑤N₂O₅。根据规律，X不可能是（）

某温度下，纯水中的c（H ⁺）=5.0×10^﹣7mol/L，则此时c（OH ^﹣）=____ mol/L．相同条件下，测得①NaHCO₃（aq）   ②CH₃COONa（aq）③NaClO（aq）三种稀溶液的pH值相同．它们的物质的量浓度由大到小的顺序是　____ ．