What the science teacher does and says       of great importance to college students.

---I saw Betty       to Grandpa Li's home just now.---Yes. She’s often seen _________ the old man with the housework.

—Are these your sheep ?—No. Mine _____ on grass at the foot of the hill.

 It was not I but you who     the first to run to the goal in that competition.

The experts along with the head teacher _____ discusssing JK Rowling’s works that _______ popular among students.