石料的抗冻性仅与材料的空隙率有关，与空隙中的水饱和程度无关。 ( )
参考答案：错
_____ the fact that David failed in the competition, his teacher thought be had done his best. [ ]
A. Although
B. Despite
C. While
D. Without
设有定义int a=2,b=3,c=4；,则以下选项中值为0的表达式是【 】。
A．(!a＝=1&&(!b==0)
B．(a＜b) &&!c||1
C．a&&b
D．a||(b+b) &&(c-a)
