题目内容

机构具有确定运动的条件是（）。

A. 自由度大于零
B. 自由度等于零
C. 自由度大于零且与原动件数相等

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复合铰链的转动副数等于（）。

A. 构件数-1
B. 构件数
C. 可动构件数-1

A grammar G is defined as a 4-tuple (VN，VT，P，S )VNis a set of nonterminalsVTis a set of terminalsP is a set of productions，each production consists of a left side,an arrow(or ‘::=’),and a right sideS is a designation of one of the nonterminalsas the start symbolV =VN ∪ VT is the alphabet of G

A. 对
B. 错

Type 3: context-free grammarsProductions are of the form X→v where v is an arbitrary string of symbols in V, and X is a single nonterminal. Wherever you find X, you can replace with v (regardless of context).

A. 对
B. 错

Type 1: free or unrestricted grammars.These are the most general. Productions are of the form u→v where both u and v are arbitrary strings of symbols in V, with u non-null. There are no restrictions on what appears on the left or right-hand side other than the left-hand side must be non-empty.

A. 对
B. 错