NameError:名称“"未定义

我正在尝试用Python编写一个脚本来结合西班牙语动词.这是我第一次使用Python编写脚本，因此这可能是一个简单的错误.运行脚本时，我输入"yo tener"并收到错误:

I am trying to make a script in Python that will conjugate Spanish verbs. This is my first time scripting with Python, so it may be a simple mistake. When I run the script, I input "yo tener" and receive an error:

回溯(最近一次通话最近):"文件第13行，在"文件中， NameError中的第1行:未定义名称"yo"

Traceback (most recent call last): File "", line 13, in File "", line 1, in NameError: name 'yo' is not defined

• 更多信息，请参见: http://pythonfiddle.com/#sthash.bqGWCZsu.dpuf

  # Input pronoun and verb for conjugation.
  text = raw_input()
  splitText = text.split(' ')
  conjugateForm = eval(splitText[0]) 
  infinitiveVerb = eval(splitText[1]) 
  
  # Set the pronouns to item values in the list.
  yo = 0
  nosotros = 1
  tu = 2
  el = 3
  ella = 3
  usted = 3
  
  # Conjugations of the verbs.
  tener = ["tengo", "tenemos", "tienes", "tiene", "tienen"]
  ser = ["soy", "somos", "eres", "es", "son"]
  estar = ["estoy", "estamos", "estas", "esta", "estan"]
  
  # List of all of the infinitive verbs being used. Implemented in the following "if" statement.
  infinitiveVerbs = [tener, ser, estar]
  
  # Check to make sure the infinitive is in the dictionary, if so conjugate the verb and print.
  if infinitiveVerb in infinitiveVerbs:
      print("Your conjugated verb is: " + infinitiveVerb[conjugateForm])