python导入模块的方法

先看代码：

import time #利用import
print "how",
time.sleep(2) #sleep()方法前面必须得有导入模块的名字time
print "are",
time.sleep(2)
print "you",
time.sleep(2)
print "today?"

from time import sleep #利用from...import...
print "how",
sleep(2) #sleep()方法前面就不要有导入模块的名字了
print "are",
sleep(2)
print "you",
sleep(2)
print "today?"

结果
how are you today?
how are you today?

区别我在代码中的注释部分已经写出了。