I found a letter ______ on the floor when I came into the classroom.
A．lying B．lay
C．lie D．lies
The children decide _____ their school yard this Friday afternoon.
A．clean B．to clean
C．cleaning D．cleaned
The boy is often heard _____in the music room. He sings very well.
A．practice singing B．to practice singing C．practiced singing
Animals are our close friends. We are supposed _____ them.
A．to protect B．protecting C．protect
The Great Green Wall can stop the wind and sand_____ to the rich land in the south of China.
A．move B．to move C．from moving
—Excuse me. Could you tell me ____get to the nearest post office?
—Sorry, I am new here.
A．how can I B．how I could
C．how to D．what I can
