摘要：“be to + 动词”结构在英语中是一个功能丰富且应用广泛的语法结构，其用法主要涉及计划安排、职责义务、命令指示、命运注定、条件假设等多个方面。以下结合权威词典例句与经典文学、影视例句，深入解析其用法。
“be to + 动词”结构在英语中是一个功能丰富且应用广泛的语法结构，其用法主要涉及计划安排、职责义务、命令指示、命运注定、条件假设等多个方面。以下结合权威词典例句与经典文学、影视例句，深入解析其用法。
一、表示计划或安排（常用于正式场合或新闻报道）
该结构用于描述预先确定的、按计划将要发生的事情，相当于“be scheduled to”或“be arranged to”。
- 例句：
1. The annual shareholders' meeting is to be held on June 15th.（《牛津高阶英语词典》）
年度股东大会定于6月15日召开。
2. The new museum is to open to the public next spring.（《剑桥英语词典》）
新博物馆将于明年春季向公众开放。
3. According to the itinerary, the delegation is to visit three cities in China.（《韦氏词典》）
根据行程安排，代表团将访问中国三座城市。
4. "The expedition is to set sail at dawn tomorrow," announced the captain.（文学场景）
船长宣布：“探险队将于明早黎明启航。”
5. The new bridge is to be opened to traffic in May.
这座新桥计划于五月通车。
6. The conference is to take place in Beijing next month.
会议定于下个月在北京举行。
7. “We are to be married in the morning,” said Romeo to Juliet.（改编自《罗密欧与朱丽叶》）
罗密欧对朱丽叶说：“我们将在清晨成婚。”
二、表示职责、义务或应该做的事（类似“should”“ought to”）
强调某人在特定情境下的责任或规定。
- 例句：
1. Employees are to submit their expense reports by the end of the month.（《朗文当代高级英语词典》）
员工应在月底前提交费用报销单。
2. Teachers are to ensure a safe learning environment for students.（《柯林斯高阶英语词典》）
教师应当为学生确保安全的学习环境。
3. The caretaker is to water the plants twice a week.（《麦克米伦词典》）
管理员每周需给植物浇两次水。
4. "You are to take care of this sacred artifact with utmost caution," the elder instructed.（虚构叙事）
长老吩咐道：“你必须极其小心地保管这件圣物。
7. You are to report to the manager as soon as you arrive.
你一到就应该向经理报到。
8. Nurses are to look after the patients with great care.
护士应当悉心照料病人。
9. “Thou art to defend thy kingdom at all costs,” the king commanded.（虚构历史场景）
国王下令：“你必须不惜一切代价保卫王国。”
三、表示命令、指示或禁止（语气较强，常用于上级对下级）
传达强制性的要求，相当于“must”或“be required to”。
- 例句：
1. Visitors are not to touch the exhibits under any circumstances.
参观者任何情况下均不得触摸展品。
2. All soldiers are to assemble at the parade ground at 08:00 hours.
全体士兵须于8点在阅兵场集合。
3. Students are to remain silent during the exam.
考试期间学生必须保持安静。
4. "You are to report to the principal's office immediately," the teacher demanded.（校园场景）
老师命令道：“你立刻去校长办公室。
5. No one is to leave the building without permission.
未经许可，任何人不得离开大楼。
6. All employees are to wear uniforms during working hours.
所有员工工作时间必须穿制服。
7. “You are to stay here and wait for my return,” the detective ordered.（影视台词）
侦探命令道：“你必须待在这里等我回来。”
四、表示命运或不可避免的结果（常用于文学作品，带有宿命感）
暗示某事是注定要发生的，通常用于过去时态。
- 例句：
1. Their paths were to cross again many years later in unexpected circumstances.
多年后，他们的命运注定会在意外的情形下再次交织。
2. The small town was to become a thriving metropolis in just a decade.
这座小镇注定在短短十年内发展为繁华都市。
3. She was never to see her childhood home again after the war broke out.（历史叙事）
战争爆发后，她再也没能回到童年的家。
4. "Little did he know that this chance meeting was to shape the course of his life."（小说片段）
“他当时浑然不觉，这次偶然相遇将决定他的人生轨迹。”
5. They were never to meet again after that fateful day.
在那个决定性的日子之后，他们再也没能见面。
6. The young hero was to become a legend in his homeland.（经典文学）
这位年轻的英雄注定会成为祖国的传奇。
7. “Little did she know that this encounter was to change her life forever.”（小说开篇）
“她当时还不知道，这次相遇将彻底改变她的人生。”
五、用于条件句中（常与if, as if 连用），表示假设
相当于“if...should”，用于虚拟或未确定的情况。
- 例句：
1. If we are to overcome this crisis, unity is essential.
若想渡过这场危机，团结至关重要。
2. If we are to succeed, we must work harder.
如果我们想要成功，就必须更加努力。
3. As if she were to disappear without a trace, leaving only questions behind.（诗歌描写）
仿佛她会消失得无影无踪，只留下无尽疑问。
4. If the project is to succeed, we need more funding and manpower.（商务语境）
项目若要成功，我们需要更多资金和人力。
5. "If humanity is to survive in space, we must master sustainable technologies," the scientist declared.（科幻设定）
科学家宣称：“人类若想在太空生存，必须掌握可持续技术。”
6. As if she were to say “I love you” without hesitation.（文学描写）
仿佛她会毫不犹豫地说出“我爱你”。
7. “If we are to survive this storm, we need a plan,” the captain said.（影视台词）
船长说：“如果我们想在这场风暴中幸存，就得制定一个计划。”
六、用于表示“可能”：
Such books are to be found in the library.
这样的书在图书馆里就能找到。
Not a sound was to be heard.
一点儿声音也听不到。
Not a soul was to be seen.
看不到一个人影。
来源：翅膀英语一点号