This is 3-D printer. And this is an artificial (人工的) ear. Can you believe that scientists printed this artificial ear by this 3-D printer?
—Peter, what’s your mother doing now? —She____________in the kitchen.
— Tomorrow is Saturday, why don’t we play basketball in the gym? —Good idea, ________ I have to see my grandparents.
—________ you open the window, please? —Yes, I can.
There are two dogs in my family. One is white,_____________ black.
I am _______________than my mother, so I am very happy.