设有文法的产生式：A->;[img=9x11]17e0a6ceb5d6d3a.jpg[/img]|[img=8x17]17e0a68dc7241f5.jpg[/img]|[img=8x14]17e0a67f314ca38.jpg[/img]，且[img=36x17]17e0bf5cef90fd0.jpg[/img][img=22x17]17e0bf5cfbfc887.jpg[/img]*[img=7x11]17e0a67d235e484.jpg[/img]，则在自上而下语法分析中，对A推导不带回溯的条件是______________:
未知类型：{'options': ['First([img=9x11]17e0a6ceb5d6d3a.jpg[/img])[img=10x12]17e0a7a15c3ab0d.jpg[/img]First([img=8x17]17e0a68dc7241f5.jpg[/img])[img=10x12]17e0a7a15c3ab0d.jpg[/img]First([img=8x14]17e0a67f314ca38.jpg[/img]) =[img=11x15]17e0b1a86b91fdb.jpg[/img]', ' First([img=9x11]17e0a6ceb5d6d3a.jpg[/img])[img=10x12]17e0a7a15c3ab0d.jpg[/img]First([img=8x17]17e0a68dc7241f5.jpg[/img])=[img=11x15]17e0b1a86b91fdb.jpg[/img]与First([img=8x17]17e0a68dc7241f5.jpg[/img])[img=10x12]17e0a7a15c3ab0d.jpg[/img]First([img=8x14]17e0a67f314ca38.jpg[/img]) =[img=11x15]17e0b1a86b91fdb.jpg[/img]与First([img=9x11]17e0a6ceb5d6d3a.jpg[/img])[img=10x12]17e0a7a15c3ab0d.jpg[/img]First([img=8x14]17e0a67f314ca38.jpg[/img]) =[img=11x15]17e0b1a86b91fdb.jpg[/img]', ' First([img=9x11]17e0a6ceb5d6d3a.jpg[/img])[img=10x12]17e0a83eaa7041a.jpg[/img]First([img=8x17]17e0a68dc7241f5.jpg[/img]）[img=10x12]17e0a83eaa7041a.jpg[/img]First([img=8x14]17e0a67f314ca38.jpg[/img]) =[img=11x15]17e0b1a86b91fdb.jpg[/img]', ' First([img=9x11]17e0a6ceb5d6d3a.jpg[/img])[img=10x12]17e0a7a15c3ab0d.jpg[/img]First([img=8x17]17e0a68dc7241f5.jpg[/img])=[img=11x15]17e0b1a86b91fdb.jpg[/img]或First([img=8x17]17e0a68dc7241f5.jpg[/img])[img=10x12]17e0a7a15c3ab0d.jpg[/img]First([img=8x14]17e0a67f314ca38.jpg[/img]) =[img=11x15]17e0b1a86b91fdb.jpg[/img]或First([img=9x11]17e0a6ceb5d6d3a.jpg[/img])[img=10x12]17e0a7a15c3ab0d.jpg[/img]First([img=8x14]17e0a67f314ca38.jpg[/img]) =[img=11x15]17e0b1a86b91fdb.jpg[/img]'], 'type': 102}
未知类型：{'options': ['First([img=9x11]17e0a6ceb5d6d3a.jpg[/img])[img=10x12]17e0a7a15c3ab0d.jpg[/img]First([img=8x17]17e0a68dc7241f5.jpg[/img])[img=10x12]17e0a7a15c3ab0d.jpg[/img]First([img=8x14]17e0a67f314ca38.jpg[/img]) =[img=11x15]17e0b1a86b91fdb.jpg[/img]', ' First([img=9x11]17e0a6ceb5d6d3a.jpg[/img])[img=10x12]17e0a7a15c3ab0d.jpg[/img]First([img=8x17]17e0a68dc7241f5.jpg[/img])=[img=11x15]17e0b1a86b91fdb.jpg[/img]与First([img=8x17]17e0a68dc7241f5.jpg[/img])[img=10x12]17e0a7a15c3ab0d.jpg[/img]First([img=8x14]17e0a67f314ca38.jpg[/img]) =[img=11x15]17e0b1a86b91fdb.jpg[/img]与First([img=9x11]17e0a6ceb5d6d3a.jpg[/img])[img=10x12]17e0a7a15c3ab0d.jpg[/img]First([img=8x14]17e0a67f314ca38.jpg[/img]) =[img=11x15]17e0b1a86b91fdb.jpg[/img]', ' First([img=9x11]17e0a6ceb5d6d3a.jpg[/img])[img=10x12]17e0a83eaa7041a.jpg[/img]First([img=8x17]17e0a68dc7241f5.jpg[/img]）[img=10x12]17e0a83eaa7041a.jpg[/img]First([img=8x14]17e0a67f314ca38.jpg[/img]) =[img=11x15]17e0b1a86b91fdb.jpg[/img]', ' First([img=9x11]17e0a6ceb5d6d3a.jpg[/img])[img=10x12]17e0a7a15c3ab0d.jpg[/img]First([img=8x17]17e0a68dc7241f5.jpg[/img])=[img=11x15]17e0b1a86b91fdb.jpg[/img]或First([img=8x17]17e0a68dc7241f5.jpg[/img])[img=10x12]17e0a7a15c3ab0d.jpg[/img]First([img=8x14]17e0a67f314ca38.jpg[/img]) =[img=11x15]17e0b1a86b91fdb.jpg[/img]或First([img=9x11]17e0a6ceb5d6d3a.jpg[/img])[img=10x12]17e0a7a15c3ab0d.jpg[/img]First([img=8x14]17e0a67f314ca38.jpg[/img]) =[img=11x15]17e0b1a86b91fdb.jpg[/img]'], 'type': 102}
举一反三
- 设有文法的产生式：A->;[img=9x11]17e0a6ceb5d6d3a.jpg[/img]|[img=7x11]17e0a67d235e484.jpg[/img]，且[img=9x11]17e0a6ceb5d6d3a.jpg[/img]不能推导出空，则在自顶向下语法分析中，对A推导不带回溯的条件是______________: 未知类型：{'options': ['First([img=9x11]17e0a6ceb5d6d3a.jpg[/img])[img=10x12]17e0a7a15c3ab0d.jpg[/img]Follow(A)=[img=11x15]17e0b1a86b91fdb.jpg[/img]', ' First([img=9x11]17e0a6ceb5d6d3a.jpg[/img])[img=10x12]17e0a7a15c3ab0d.jpg[/img]First(A)=[img=11x15]17e0b1a86b91fdb.jpg[/img]', ' First([img=9x11]17e0a6ceb5d6d3a.jpg[/img])[img=10x12]17e0a83eaa7041a.jpg[/img]Follow(A)=[img=11x15]17e0b1a86b91fdb.jpg[/img]', ' First([img=9x11]17e0a6ceb5d6d3a.jpg[/img])[img=10x12]17e0a83eaa7041a.jpg[/img]First(A)=[img=11x15]17e0b1a86b91fdb.jpg[/img]', ' 其他4个答案都不对'], 'type': 102}
- 设随机变量(X,Y)在区域｛(x,y): 0<|y|< x <2｝内均匀分布，则以下结果正确的是 A: 当0<x<2时，[img=96x25]1802dded7db6eef.png[/img]. B: E(X)=4/3 C: 当0<|y|<2时,[img=105x45]1802dded872b92f.png[/img]. D: P(X<1)=0.5 E: 当0<x<2时,[img=110x45]1802dded915de6e.png[/img]. F: E(X)=2/3 G: 当0<y<2时，[img=95x43]1802dded9a54300.png[/img].
- 在下列命题中:如果f(x)=[img=28x44]17e0bf9914bb2f1.png[/img],那么[img=27x29]17e0bf97582597b.png[/img]f(x)=0;如果f(x)=[img=28x44]17e0bf992111a1c.png[/img],那么[img=27x29]17e0bf97582597b.png[/img]f(x)=0;如果f(x)=[img=55x44]17e0bf992d8de0a.png[/img],那么[img=29x29]17e0bf9939482bb.png[/img]f(x)不存在;如果f(x)=[img=87x53]17e0bf99450fa82.png[/img],那么[img=27x29]17e0bf97582597b.png[/img]f(x)=0。其中错误命题的个数是( A: 0 B: 1 C: 2 D: 3
- 设f(x)在|x|>;a上有定义，若___________，使得当|x|>;X时，恒有|f(x)-A|<;ε, 称[img=57x14]17de8197cad5b33.png[/img]时函数f(x)有极限A，记作[img=33x32]17de8197d6e5e38.png[/img][img=71x25]17de8197e309ab5.png[/img]。 A: 存在ε>;0, 存在X>;0 B: 任意ε>;0, 存在X>;0 C: 存在ε>;0, 任意X>;0 D: 任意ε>;0, 任意X>;0
- 下面是图的拓扑排序的是？(多选)[img=340x240]1802faef6ebcc2a.png[/img] A: 2 8 0 7 1 3 5 6 4 9 10 11 12 B: 2 8 7 0 6 9 11 12 10 1 3 5 4 C: 8 2 7 3 0 6 1 5 4 9 10 11 12 D: 8 2 7 0 6 9 10 11 12 1 3 5 4