---Why do you look so sad?---There are so many problems_______.
The medicine bought at a high price turned out to have no _____.
Please tell me how global warming _____. I am still in the dark.
It is high time that we ____ the amount of carbon dioxide in our daily life.A. reduce B reduced C will reduce D reduces
It rained that day and ___ the baseball game was called off.
It is not until the disease has progressed to AIDS ____a person begins to look sick.