单项选择题
假设某程序语言的文法如下：
S→a|b|(T)
T→TdS|S
其中，VT={a，b，d，(，))；VN={S，T}，S是开始符号。考察该文法，句型(Sd(T)db)是S的一个(28)。
其中(29)是最左素短语，(30)是该句型的直接短语。
(74)
- A.最左推导
B．最右摊导
C．规范推导
D．推导
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