>>> print('1',os.path.join('aaa','/bbb','ccc.txt'))
1 /bbb\ccc.txt
>>> print('1',os.path.join('/aaa','/bbb','ccc.txt'))
1 /bbb\ccc.txt
>>> print('1',os.path.join('/aaa','/bbb','/ccc.txt'))
1 /ccc.txt
>>> print('1',os.path.join('/aaa','bbb','ccc.txt'))
1 /aaa\bbb\ccc.txt
>>> print('1',os.path.join('/aaa','bbb','/ccc.txt'))
1 /ccc.txt
特別地，如果前面的字符里有C：，則無(wú)論如何也會(huì)被放到結(jié)果里！
