为了省钱，他开始乘坐公共交通而不开车。

He started to ___economize by taking public transport instead of driving.

我们通过关掉不用的灯来节约用电。

We ___conserve electricity by turning off unused lights.

我们尽量节省能源以减少开支。

We try to ___economize on energy to cut down expenses.