They have no paper_______.
A：to write
B：to write with
C：write on
D：to write on
You can have a good view of Nanjing at the top of Zijin Mountain ______ a clear day.
2011中国城市竞争力测评纳入了“幸福感”指标，北京的产业层次竞争力排名第一，而在幸福指数一项排名第9。其原因为（）
函数f（x）=log22x﹣log2x2，则函数f（x）在区间12，2上的值域是 ____
