【分析】
本题为英语书面表达题，要求根据给定的购物清单补全短文，需使用How much或How about询问价格，语句通顺且不少于50词。解题时，先明确清单中的物品及对应信息：爸爸的黑色鞋子120元、妈妈的裙子90元、杰克的帽子26元；再按合理的购物顺序（先为爸爸选鞋，再为妈妈选裙，最后选自己的帽子）展开，运用规定的价格询问句型，补充自然的购物情节，确保内容连贯、符合要求。
【解析】
写作步骤如下：1. 承接开头，先描述为爸爸挑选鞋子：点明鞋子是黑色的，用“How much are they?”询问价格，对应清单给出120元，说明爸爸买下；2. 接着写妈妈的裙子：用“How much is the dress?”询问价格，对应90元，说明妈妈喜欢；3. 最后写自己的帽子：用“How much is this cap?”询问价格，对应26元，表达觉得便宜；4. 收尾说明付款，呼应结尾的“We are all happy.”，确保语句通顺，满足词数要求。
【答案】
One possible version:
A happy shopping trip with my parents
Hi, I'm Jack. I go shopping with my parents in a shop. First, we find a pair of shoes for my dad. They are black and cool. "How much are they?" Dad asks. The assistant says, "They are 120 yuan." My dad takes them. Then we see a nice dress. Mum asks, "How much is the dress?" "It's 90 yuan," the assistant says. Mum likes it very much. Finally I find a cool cap. I want to buy it. I ask the assistant, "How much is this cap?" She says, "It's 26 yuan." That's cheap! We pay the money and buy all the things. We are all happy.
【知识点】
英语书面表达，购物话题用语，价格询问句型
【点评】
本题结合日常购物场景考查英语写作能力，要求学生运用指定句型，结合给定信息创作，既考察基础句型的掌握，又考察语篇连贯组织能力，是初中英语常见的写作题型。
【难度系数】
0.5