下列哪种方式是生物为适应低温环境而采取的措施 ( )
A．夏眠
B．穴居
C．迁移
D．昼伏夜出
参考答案：A
I think he wouldn't come unless he ______. [ ]
A. was inviting
B. was invited
C. invited
D. invites
环境与环境保护的概念是什么？
