Hidden _____ by a big tree, his house was not to be seen.

If you don’t know the word, you can _____ in the dictionary.

We should pay much attention to the plants which are .

Newton is known as a gifted scientist withvery human weaknesses who stood at the point in history _______ magic ended andscience began.

Have you returned the book to the library _______ —Yes, I have _______ retuned it.