一、动词不定式作表语
1．动词不定式放在be, become, sound, taste, seem, appear等系动词后面常表示将来的动作或起解释说明的作用，其主语常常是wish, idea, task, purpose, duty, job, goal, aim, way等表示意向、打算、计划的词及what 引导的主语从句等。
Her wish is to become a key college student after graduating from high school.
她的愿望是高中毕业后成为一名名校大学生。
What he wanted to suggest is to cut down the price and increase the sales.
他想建议的是降低价格，增加销售量。
2．动词不定式作表语时也常用来表示预定要发生的动作，或表示未来的可能性或假设。
The students are to meet at the school gate tomorrow.
明天学生们将在学校大门口见面。
Her plan is to be a failure.
她的计划是注定要失败的。
