简述外部环境特性。
参考答案：
（1）环境不确定性；（2）环境竞争性；（3）环境合作性；（4）所在行业成长性。
Indeed,thanks to the good ideas of lots of people,like the cycling fans in the 1960s,many people around the world______the city centre streets without cars for many years.
A．have enjoyed
B．enjoyed
C．have been enjoying
D．have been enjoyed
高良姜的功效是（）
A.祛寒止痛，理气和胃
B.散寒止痛，疏肝下气
C.温中降逆，温肾助阳
D.温中止痛
E.温中止痛，杀虫
