Your parents _______you many things in their lifetime, but you may not realize that until they are gone.

When I arrived, Bryan took me to see the house___ I would be staying.

It wasn’t until dark _________ he found _________ he thought was the correct way to solve the problem.

Will the new iphone cost a lot— I ________ think so. Apple’s products are usuallyexpensive.

How about your travel? — You can hardly imagine what difficulty we have had ______ the vast desert. [ ]