________ 200BC, the Silk Road, which was the route for trade between the East and the West, was in use.

The charity sale our school organizes every year has taught us much. _______ we would never have learned it in class.

After two years’ research, we now have a __________ better understanding of the disease. 

This is only a solution that can be adopted to solve the problem       , so you have to find a better way.

 — It's so cold today.    — Yes, it's       colder than it was yesterday.