公司正在与一家建筑承包商签订协议。

The company is ___contracting with a builder for the project.

天气变冷时，金属管道会收缩。

Metal pipes start ___contracting when the temperature drops.

很多孩子在幼儿园容易感染感冒。

Many children at kindergarten end up ___contracting colds easily.