Often looking at your daily behavior from a different ______ will help you change your  actions for the better. 

I listened to Dr. Johnson’s lecture about biology, but I failed to get its key ____.

All the apartments have been sold out while the building is still _____.

---- Water can dissolve almost anything and give nutrients to creatures. ---- Yes, and that’s one of its __________.

The rescue team didn’t leave until they were able to find no ______ of life in the ruins after the destructive quake.