Read and order 给打乱顺序的句子重新排序。
① Ok, I'll take it.
②How much is it?
③Can I help you?
④What size?
⑤It's ninety yuan.
⑥Size six.
⑦Yes, please. I want a pair of shoes.
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①地表千沟万壑,湖泊星罗棋布
②全部退耕植树种草,减少水土流失
③陡坡地退耕要与发展多种经营相结合
④窑洞和信天游是富有特色的黄土风情
为确保生命安全,下列处理事故的方法正确的是( )