People have cut down many trees every year, so there will be fewer trees, ________?

There used to be a hospital , __________?

— You didn’t sleep well last night, did you?  —      , so I feel tired now. 

The book cost you 50 yuan, _______?

-The captain（船长）of the Sewol ferry（岁月号）hardly do anything to help the passengers on the ferry。          ？-              ，so over two hundred people lost their lives in the accident。