21世纪人类的生存环境面临的八大挑战之一是( )。
A．传染病威胁人类健康
B．土地严重沙化
C．世界经济逐渐衰退
D．海平面水位下降
参考答案：B
企业减灾预案主要分几个阶段？
Some people are born to have a very good memory whereas many other people are born to have a memory like a ______.
A. sleeve B. sieve C. button D. basket
