13 ___ had they reached the 30th floor ____ they realized that they had forgotten to take the key

_Stressful environments lead to unhealthy behaviors such as poor eating habits,which_______increase the risk of heart disease

Only when all the fish in the lake died ________ how serious the pollution was.[ ]

_______ do you play with your old classmates— Not very often.

It’s generally believed that the popular South Korean drama Man From the Stars is ________ in creative storylines as in pretty faces and fashion.