Of all the methods they provided, ________ is of any help for solving the math problem.

Someone knocked at your door just now,but I didn’t see who     was.

---Is there _________ new in today’s newspaper?---Yes, I will read it to you.

—It's said that Tom is a wise manager in your company.—Oh, no, he is ________  but a wise leader.

When you go outing with your sisters, you must see to ________ that they are safe.