题目

【小题1】We had a long __________ (讨论)about the plan.【小题2】Driving on mountain roads always makes me __________ (紧张).【小题3】I__________ (写 )her several letters, hut she didn't reply.【小题4】 He introduced his lovely daughter to the guests __________ (高兴地 )【小题5】I couldn't decide  __________(是否)or not to go to the party. 答案：【小题1】 discussion  【小题1】nervous  【小题1】 wrote    【小题1】happily  【小题1】whether解析:略对于万有引力定律的表达式，下列说法中正确的是(     ).A．公式中G为引力常量，它是由实验测得的，而不是人为规定的B．当r趋于零时，万有引力趋于无限大C．两物体受到的引力总是大小相等、方向相反，是一对平衡力D．两物体受到的引力总是大小相等的，而与m1、m2是否相等无关