他们引入了一个系统，通过该系统人们可以慢慢偿还贷款。

They've introduced a system ___whereby people can pay back their loans gradually.

支持单性别教育的人引用研究，通过这些研究学生在专注的环境中表现更好。

Supporters of single-sex education cite research ___whereby students perform better in focused environments.

公司建立了一个协议，根据该协议所有员工必须立即报告安全事件。

The company established a protocol ___whereby all employees must report safety incidents immediately.