遣词造句
1. 当你在室内时，一定不要从高楼向外跳。(jump out of)

2. 你最好远离桥梁。(keep away from)

3. 当你在山中时，你应当小心落下的石头。(be careful with)

1. When you're inside, you mustn't jump out of the high building.
2. You'd better keep away from bridges.
3. When you are in the mountains, you should be careful with falling rocks.

【分析】本题要求结合中文提示与指定短语完成英语句子，解题时需先确定句子的核心句式（如时间状语从句、情态动词句式），再准确运用括号内的固定短语，注意名词形式、情态动词的恰当使用，确保句子符合英语表达习惯。
【解析】1. 时间状语“当你在室内时”译为When you're inside，表禁止的情态动词用mustn't，短语“从高楼向外跳”为jump out of the high building，组合得句子：When you're inside, you mustn't jump out of the high building.
2. “你最好”对应You'd better，短语“远离”是keep away from，“桥梁”用复数形式bridges（表泛指），组合得：You'd better keep away from bridges.
3. 时间状语“当你在山中时”译为When you are in the mountains，表建议的情态动词用should，短语“小心”是be careful with，“落下的石头”译为falling rocks（falling作定语表动作），组合得：When you are in the mountains, you should be careful with falling rocks.
【答案】1. When you're inside, you mustn't jump out of the high building.
2. You'd better keep away from bridges.
3. When you are in the mountains, you should be careful with falling rocks.
【知识点】情态动词用法，固定短语搭配，时间状语从句
【点评】本题为基础英语遣词造句题，侧重考察常用短语与情态动词的运用，是巩固英语基础的典型题型，掌握核心短语和基本句式即可完成。
【难度系数】0.3