(2013·四川高考)Nowadays people are more concerned about the environment ________ they live.

It was when I arrived home _____ I realized I had left my bag in the library.

Everyone in our class works as hard as theycan ________ to enter a good college

Evenifhehastime,he_____shoppingintownonSunday.

of the household garbagerecycledor reused since the new technology was applied.