写英语剧本的步骤如下：

确定剧本的基本信息

标题：为剧本起一个吸引人的标题。

介绍（Introduction）：简要介绍剧情、主要人物和故事背景。

人物描述（Characters）：

详细描述每个主要人物的性格、外貌、动机和背景。确保每个人物至少有3句话的描述。

剧情构思（Plot Ideas）：

构思故事的主要情节和转折点，确保至少有10句话的描述。

剧本格式（Format）：

场景标题（Scene Heading）：使用大写字母，并标明内外景。

动作描述（Action / Scene Directions）：简洁地描述场景中的动作和事件，避免心理描写和其他非视觉化的描述。

对话（Dialogue）：

编写自然、生动的对话，确保对话符合人物的性格和情境。

表演要求（Performance Requirements）：

根据班级人数，控制总表演时间在2节课（90分钟）内，每组表演时间不少于6分钟。

审查和修改（Review and Revision）：

完成初稿后，仔细审查剧本，检查语法、拼写和格式错误，并进行必要的修改和优化。

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Title: A Chance Encounter

Introduction:

In a bustling city, two strangers meet by chance and discover they share a common goal.

Characters:

Old Lady：A kind-hearted woman in her 70s, who has lost her beloved dog.

Myra：A young woman in her 20s, a dog trainer looking for a new job.

Enid：A middle-aged woman in her 40s, a pet store owner.

Mrs. Morrison：A neighbor who knows everyone in the community.

Jonnie：A teenager, Myra's friend who is eager to help.

Mrs. Grant：The postman who delivers important letters.

Plot Ideas:

1. The old lady, Myra, Enid, Mrs. Morrison, Jonnie, and Mrs. Grant all have different stories related to their pets.

2. Myra finds a lost dog and takes it to Enid's pet store, where she meets Mrs. Morrison.

3. Mrs. Morrison tells Myra about a community event where people can adopt dogs.

4. Myra decides to participate in the event and enlists Jonnie's help to find the lost dog's owner.

5. The group works together to reunite the dog with its owner, leading to a heartwarming moment at the event.

Performance Requirements:

Total performance time: 90 minutes

Minimum group performance time: 6 minutes

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通过以上步骤，你可以完成一个结构完整、内容丰富的英语剧本。记得在写作过程中保持语言简洁明了，便于演员理解和表演。