公司的快速扩张让每个人都感到惊讶。

The rapid ___expansion of the company surprised everyone.

该市的计划包括将公共交通扩展到郊区。

The city's plan includes the ___expansion of public transport to suburbs.

宇宙的膨胀是宇宙学中的一个关键概念。

The ___expansion of the universe is a key concept in cosmology.