With an appropriate modal verb: (1)Vicky's engagement ring is en

With an appropriate modal verb:
(1)Vicky's engagement ring is enormous! It ____ have cost a fortune.(2)We are wondering how they challenge that expert.
【正确答案】：must;dare
【题目解析】：考点点击本题考查情态动词。要点透析】第一句意为: Vicky的订婚戒指非常大,肯定花了大价钱!表示对肯定情况的推测用 must dare意为“敢,敢做”,dare作情态动词时,主要用于疑问句或否定句中,符合题意。第二句意为:我们很好奇他们怎么敢挑战那位专家的。