1．The festival is one of the four (large) ice and snow festivals in the world!
largest 解析：考查比较等级。此处表示四个最大的冰雪节之一，故填largest。
2．It is an (attract) place full of ancient bridges, traditional hotels and restaurants all built around an amazing water network that is part of the Beijing—Hangzhou canal, the (long) canal in the world.
attractive；longest 解析：第一个空修饰place，故应用形容词attractive，表示“吸引人的”。第二个空前面有the，空后有比较范围in the world，故应填最高级longest，表示“最长的”。
3．It was (amaze) that our class won the second place. Our efforts paid off!
amazing 解析：此处It为形式主语，真正的主语为that引导的主语从句。系动词be后跟形容词，此处意为“令人感到吃惊的”故填amazing。
4．Thinking his key was controversial，I devoted myself to the problem heart and soul, trying to figure it out in a different way. Twenty minutes
(late), I succeeded in finding, in my opinion, the right key.
later 解析：句意：由于认为他的答案有争议，我全心全意地研究这一问题，试图用不同的方法把它解出来。二十分钟以后，我找到了自己认为正确的答案。late 表示“迟，晚”，later 表示“后来，以后”。
