Listen!Our science teacher _______________the use of the robot.
explains
explained
is explaining
has explained
Mom was cooking ________ Dad was reading newspapers.
It’s late. David washes his face _______ goes to bed.
()—Do you believe that paper is made ________ wood? —Yes, I do. And you can see that books are made ________ paper.
Guangdong is ____ the south of China .
I read an article ________ a young writer ________ the UK last week.