—Do you know       ? —I’m not sure, maybe he is an artist.

— ____ you sing the English song?— Yes, I can.

Whenever my grandmother calls just to chat with me，I drop everything and enjoy the moment，knowing these times__________pass．

 —Look at the boy running on the ground. Is it David?—It      be him. I saw him go to the teacher’s office just now.

—I want to know if I _______________smoke here. —No, you ______________. Could you see the sign “ No Smoking” there?