The technological advances of the twentieth century have been brought about an alarming reduction of our natural resources.
—David, are you listening to me?—Sorry, Dad. I ________ to make sense of what the reporter said.
—Look! Someone ________ the floor.—Well, it wasn't me. I went shopping just now.
It's said that they ________ a better life ever since they moved to the US.
—Ouch! You hurt me.—I'm sorry. But I ________ any harm. I ________ to drive a rat out.
In general, most tennis ________ on hard courts or on clay.