We can see only one of the doors ______.

_______do you spare time to visit your parents every month?-Twice.

Afghans used to hold big weddings, costing thousands of dollars, in a county _____ the average annual income is less than $400

It’s said that scientists have ________ a way todeal with the disease(疾病)—Really That’s great!

Do I have to do it right now–No, you _____. You can do it at any time.