why is one test case alwsys failing here?

Question

https://www.sololearn.com/coach/64?ref=app word=str(input())
x=word.split()
for i in range(len(x)):
if(x[i].isalpha()==False):
if(int(x[i])==0):
x[i]="zero"
elif(int(x[i])==1):
x[i]="one"
elif(int(x[i])==2):
x[i]="two"
elif(int(x[i])==3):
x[i]="three"
elif(int(x[i])==4):
x[i]="four"
elif(int(x[i])==5):
x[i]="five"
elif(int(x[i])==6):
x[i]="six"
elif(int(x[i])==7):
x[i]="seven"
elif(int(x[i])==8):
x[i]="eight"
elif(int(x[i])==9):
x[i]="nine"
else:
x[i]=x[i]
str1=' '.join(map(str,x))
print(str1)

Answer 1

"Take a phrase and replace any instances of an integer from 0-10 and replace it with the English word that corresponds to that integer."

10 = ten ;)

Answer 2

Post the code