NLTK语法解析错误价值eRROR：无法解析行24

Question

我正在使用Python进行自然语言处理 - 使用自然语言工具包分析文本，我正在第10章，练习1：

    >Select three or four contiguous sentences from a book for children. A possible source of examples >are the collections of stories in nltk.corpus.gutenberg: bryant-stories.txt, burgess->busterbrown.txt and edgeworth-parents.txt. Develop a grammar which will allow your sentences to be 
    >translated into first order logic, and build a model which will allow those translations to be >checked for truth or falsity.

我正在尝试与Burgess-Busterbrown.txt corpus中的以下句子一起工作

    >Little Joe Otter was in a terrible rage. It was a bad beginning for a
    >beautiful day and Little Joe knew it. But who wouldn't be in a rage if
    >his breakfast was taken from him just as he was about to eat it? Anyway,
    >that is what Little Joe told Billy Mink.

：遵循FCFG语法文件＆amp;解析代码：

    % start S
    S[SEM=(?vp + '(' + ?nps + ',' + ?npo + ')')] -> CONJ[SEM=?conj] NP[SEM=?nps] VP[SEM=?vp] NP[SEM=?npo]
    S[SEM=(?vp + '(' + ?nps + ')')] -> CONJ[SEM=?conj] NP[SEM=?nps] VP[SEM=?vp] AdvP[SEM=?advp]
    S[SEM=(?vp + '(' + ?nps + ',' + ?npo + ')')] -> NP[SEM=?nps] VP[SEM=?vp] NP[SEM=?npo]
    S[SEM=(?vp + '(' + ?nps + ',' + ?s + ')')] -> CONJ[SEM=?conj] NP[SEM=?nps] VP[SEM=?vp] S[SEM=?s]
    S[SEM=(?vp + '(' + ?nps + ',' + ?s + ')')] -> NP[SEM=?nps] VP[SEM=?vp] S[SEM=?s]
    S[SEM=(?vp + '(boy)')] -> P[SEM=?p] VP[SEM=?vp] AdvP[SEM=?advp]
    S[SEM=(?vp + '(boy,' + ?np +')')] -> P[SEM=?p] VP[SEM=?vp] NP[SEM=?np]
    S[SEM=(?s1 + ?conj + ?s2)] -> S[SEM=?s1] CONJ[SEM=?conj] S[SEM=?s2]
    S[SEM=(?vp + '(' + ?np + ')')] -> AdvP[SEM=?advp] AdvP[SEM=?advp] VP[SEM=?vp] NP[SEM=?np]
    
    VP[SEM=?v] -> V[SEM=?v]
    VP[SEM=?v] -> Aux[SEM=?aux] V[SEM=?v]
    NP[SEM=?n] -> N[SEM=?n]
    NP[SEM=?n] -> DET[SEM=?det] N[SEM=?n]
    NP[SEM=?n] -> DET[SEM=?det] Adj[SEM=?adj] N[SEM=?n]
    
    AdvP[SEM=''] -> P[SEM=?p] P[SEM=?p] NP[SEM=?np]
    AdvP[SEM=''] -> Adv[SEM=?adv]
    
    
    CONJ[SEM='&'] -> 'and'
    CONJ[SEM='->'] -> 'So'
    P[SEM=?p] -> 'a' | 'for' | 'wouldn't' | 'if' | 'from' | 'as' | 'to' |'Anyway'
    Adv[SEM=''] -> 'about'
    Adv[SEM=''] -> 'just'
    Adv[SEM=''] -> 'that'
    Adj[SEM=''] -> 'little'
    Adj[SEM=''] -> 'terrible'
    Adj[SEM=''] -> 'bad'
    Adj[SEM=''] -> 'beautiful'
    DET[SEM=''] -> 'a' | 'the'
    N[SEM='Joe'] -> 'Joe' | 'he' |'Otter' |'him' | 'his'
    N[SEM='Billy'] -> 'Bilyu' |'Mink'
    N[SEM='rage'] -> 'rage'
    N[SEM='beginning'] -> 'beginning'
    N[SEM='day'] -> 'day'
    N[SEM='breakfast'] -> 'breakfast' | 'it'
    V[SEM='be'] -> 'was' | 'be'
    V[SEM='in'] -> 'in'
    V[SEM='knew'] -> 'knew'
    V[SEM='take'] -> 'taken'
    V[SEM='eat'] -> 'eat'
    V[SEM='tell'] -> 'told'


    parser = load_parser('grammar_test.fcfg')
    sentence = 'Little Joe Otter was in a terrible rage'
    tokens = sentence.split()
    trees = list(parser.parse(tokens))
    for tree in trees:
       print (tree.label()['SEM'])

我会收到以下错误：

    > ValueError: Unable to parse line 24: P[SEM=?p] -> 'a' | 'for' | 'wouldn't' | 'if' | 'from' | >'as' | 'to' |'Anyway' Unterminated string
    

诚然，我不太擅长理解语法部分，我使用其他句子从其他人那里调整了其他问题的语法部分，以获取相同的问题。我在做什么错或失踪？我如何正确地进入一阶逻辑？我尝试了其他版本的语法，但是它们给出了“语法不涵盖某些输入单词”错误，这比上述错误更接近，但无论哪种方式都没有起作用。

感谢任何帮助。