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Visiting the London EyeAvoid Peak TimesThe London Eye is busiest between 11 a.m. and 3 p.m. during the UK school holidays, and is quieter at the beginning and end of their opening hours, which vary throughout the year. As a rough guide, summer hours are 10 a.m. to 8.30 p.m. and winter hours are 11 a.m. to 6 p.m., but do check in advance on their site for the hours on the day you plan to go. It's worth bearing in mind that it closes for around two weeks every January, for annual maintenance (维护).Buy Tickets OnlineBuying tickets online will allow you to skip the initial ticket office line an一个钢筋三角架三边长分别是20厘米、50厘米、60厘米，现在再做一个与其相似的钢筋三角架，而只有长为30厘米和50厘米的两根钢筋，要求以其中一根为一边，从另一根上截下两段（允许有余料）作为两边，则不同的截法有多少种？写出你的设计方案，并说明理由．