In [20]:

    

def reverse(s):
    for i in range(len(s)-1, -1, -1):
        print(s[i], end = '')

line = '123456'
print(line)
reverse(line)


    

    




123456
654321

In [35]:

    

def print_zhijiao_tri(line):
    for i in range(1, line+1):
        for j in range(0, i):
            print('*', end = '')
        print()
        
def print_dengyao_tri(line):
    for i in range(1,line+1):
        for k in range(0, line+1-i):
            print(' ', end= '')
        for j in range(1, i*2):
            print('*', end = '')
        print()
        
print_zhijiao_tri(5)
print()
print_dengyao_tri(6)
print()


    

    




*
**
***
****
*****

      *
     ***
    *****
   *******
  *********
 ***********

In [51]:

    

def difine(words):
    if words.endswith('s') or words.endswith('ch') or words.endswith('sh'):
        print(words + 'es')
    elif words.endswith('y'):
        print(words[:-1] + 'ies')
    elif words.endswith('f'):
        print(words[:-1] + 'ves')
    else:
        print(words + 's')
        
word = input('请输入一个英语单词：')
difine(word)


    

    




请输入一个英语单词：leaf
leaves