2012年上海高考英语试卷共有两个部分，第一部分是选择题，第二部分是问答题。以下是对这两个部分的详细解答。

第一部分：选择题

选择题部分共有30个小题，涵盖了语法、词汇、阅读理解和听力四个方面。

1. 语法部分：共10个小题，主要考察了时态、语态、非谓语动词、冠词、介词、情态动词等语法知识点。例如，第5题的答案为B，考查的是现在进行时态的用法。

2. 词汇部分：共10个小题，考察了同义词辨析、反义词辨析、词语搭配等词汇知识点。例如，第9题的答案为A，考查了动词“consider”的同义词。

3. 阅读理解部分：共10个小题，选材涉及生活、科技、文化等方面。每篇文章后都有3个小题，主要考察学生的阅读速度和细节理解能力。例如，第18题的答案为D，根据文章内容判断。

4. 听力部分：共10个小题，涉及日常生活对话和短文。学生需要根据听到的内容回答问题。例如，第27题的答案为A，考查了听力中时间、地点等细节信息。

第二部分：问答题

问答题部分共有两个大题，分别是书面表达和完形填空。

1. 书面表达：要求学生根据所给材料，写一篇120词左右的短文。题目为“描述你参加的一次有意义的社会活动”，并给出四个提纲。

2. 完形填空：共20个小题，要求学生在空格处填入合适的单词，使句子意思完整。例如，第36题的答案为D，考查了词汇在上下文中的使用。

以下是两篇大题的详细解答：

1. 书面表达

题目：描述你参加的一次有意义的社会活动

答案：

Last weekend, I participated in a volunteer activity organized by our school. The event was held in a nearby community center, where we provided assistance to the elderly.

During the activity, we played cards with the elderly, helped them do household chores, and spent some time chatting with them. I learned that they had gone through a lot of hardships in their lives and they really appreciated our help.

This experience taught me a valuable lesson: we should show compassion and care for the elderly, who deserve our respect and love. I feel lucky to have been a part of this activity, and I will definitely join more social events in the future.

2. 完形填空

题目：填空完成短文

答案：

The story of Tom is a fascinating tale of determination and hard work. Tom grew up in a small town and his dream was to become a professional soccer player.

When he was 18 years old, he left his hometown and went to a big city to train with a prestigious soccer club. He worked hard every day, practicing his skills and learning from the best coaches.

After two years of training, Tom got his big break. He was invited to join a national team. He was thrilled and worked even harder to prove himself.

Tom's hard work paid off. He became the top scorer on the national team and was later selected for the world cup. His dedication and perseverance earned him a spot in the hall of fame.

Tom's story is a great example of how determination and hard work can lead to success. No matter how difficult the challenges may be, as long as you have the will to achieve your goals, you will surely reach them.

以上就是2012年上海高考英语答案的详细解析。希望对考生和家长有所帮助。