沙漠中植物稀少,起决定作用的主要非生物因素是( )
A:阳光
B:温度
C:空气
D:水
设集合A={x||x﹣a|<2},B={x|2x-1x+2<1},若A⊆B.求实数a的取值范围.
选择合适的选项完成对话。
Cheng Jie: Good morning!
Amy: ____
Cheng Jie:Nice to meet you.
Cheng Jie: ____
Amy: My name is Amy.
Cheng Jie:____
Amy: I'm from the USA.
A. Where are you from ? B. Nice to meet you, too.
C. What's your name? D. Good morning.
若n为正整数,且x2n=3,则(3x3n)2的值为____.