What is the price of this face mask? How long is the Mekong River?

1.What is the price of this face mask?
->(cost).............................................
2.How long is the Mekong River?
->What........................................
3.How wide is the west lake?
->What........................................
4.You should't eat too much meat.
->You'd......................................
5.Why were you absent from class last Monday?
->Why did't.......................