With an appropriate modal verb: (1)Children under 12 years of ag

With an appropriate modal verb:
(1)Children under 12 years of age in that country ____ be under adult supervision when in a public library. (2)You can't imagine that a well-behaved gentleman ____ be so rude to a lady.
【正确答案】：must; should
【题目解析】：【考点点击】本题考查情态助动词。【要点透析】must意为“必须;一定要”,语气强烈。 should在此处意为“竟然”,表示感到意外或吃惊。