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已知△ABC与△ 的相似比为2：3，△ 与△ 的相似比为3：5，那么△ABC与△ 的相似比为____。

根据材料内容，选择正确答案。

    He is quiet and shy. He likes to hide his eyes behind his hair. He doesn't smile very often. However, if you talk to him about music, he'll have a lot to say.

This is Jay Chou, the 24-year-old Taiwanese pop king(天王). His fans are so excited because he will sing songs in Beijing on September 12. Those songs are from his new album(唱片), "Ye Huimei", and the album was released(发行) in July and was named after his mother.

    Chou grew up just with his mother. He did not talk much and did badly in many school subjects.

His mother noticed the boy's special interest in music and sent him to learn piano when he was only three years old. He loved it and kept on practicing.

Chou is not very handsome. He does not speak clearly when he sings or talks. But the singer has huge crowds of fans. "He is really good at music. It makes him attractive(有魅力的) to me," said Liu Jiajun, a Junior 2 student in NO.101 Middle School in Beijing.

    "He is true to himself. He never follows others," said Zhang Yujie, a Junior l girl at Huaibei Middle School in Sihon9, Jiangsu Province.

材料一：“北京人”用火的证据十分明显。发掘“北京人”化石地点的中段靠近南北裂缝的堆积时，曾发现过三层灰烬。上层灰烬很厚，最厚深过六米，位于整个堆积的中上部；中层灰烬较薄，最厚深达四米，位于堆积的中下部；下层灰烬最薄，最厚处只有一米，位于堆积的底部……

材料二：灰烬的发现不仅证明了“北京人”已经使用了火，而且灰烬在同一层中，有时很厚，有时很薄，有时又间断，又可以证明他们已经有了一定的控制火的能力。

材料三：人类能够使用和管制火，是历史上的一件大事，因为这必须是在漫长的岁月中累积了绝对化经验，有了相当的智慧才能办到的。正因为“北京人”能够如此，才进一步证明了他们对对付自然已有了一定的办法。

——贾兰坡《“北京人”的故居》

理想变压器原、副线圈匝数之比为2：1，原线圈接入如图乙所示的正弦式交流电压，副线圈接一个R=55Ω的负载电阻，电流表、电压表均为理想电表，则下述结论正确的是（   ）