以下对于字符串的相关操作,正确的输出结果是哪些选项? A. >>> 'Life is short, you need Python.'.find('you') 15 B. >>> seq = [1, 2, 3, 4]; >>> sep = '+'; >>> sep.join(seq) '1+2+3+4' C. >>> print '%05.3f' % math.pi 3.1416 D. >>> print 'you' in 'Life is short, you need Python.' True