迅速壮大的英语短语怎么说

迅速壮大的英语短语可以用 "rapidly expanding" 来表示。这个短语指的是事物在短时间内迅速发展、增长。例如：

The company has been rapidly expanding its operations in Asia.
The city's population has been rapidly expanding in recent years.

如果你想表达的是一种具体的速度，你也可以在 "rapidly" 后面加上一个表示速度的形容词，比如 "rapidly increasing"、"rapidly growing" 等。