Professor Lee failed many times but he ________found a good way to solve the problem.

 Seeing the coach nodding ________ to her, the little dancer was no more nervous and went on with her performance.

---Have you been to the National Theatre? ---No, but I’ve         bought two tickets for the concert to be given this weekend.

---How did you find the albums ’ Music Voyager’ and ’Heaven’ by JJ Lam?--- Wonderful. It’s ____ worth ________.

Although modem organic food has become very popular, many people can' t figure out the difference between organic foods and ______ grown foods．