—What do you think of the meal we have just had?—It is well worth ______ is changed for it.

---Do you have anything to say for yourself?---Yes, there is one point ________ I must stick to.

After living with his grandparents in the countryside for ten years, the boy returned to the big city ____ his parents worked.

That dog ought to be destroyed        it attacks any more children.

—The experiment is of particular importance.　　　　—I see. We will carry on with it ________ we can get enough money.