在下列各句的空格内填上一个适当的完整的单词，该词的首字母已给出。

1. You have more pens than I, but m ___   are better than yours.

2. The doctors and nurses tried every effort to save the d __    boy, but it didn't help.

3. Would you please write down your name, home a       _ ,and mobile phone number?

4. The shoes are too expensive. I can't a     __  them.

5. Mobile phones must be kept off d   ___  the meeting．

根据植物与环境统一的原理，生长在沙地的树木最好栽植在（）上。