请根据句子意思,选用适当词或用所给词的适当形式填空。 11. Because of the lack of the ______ (motivate)to study, he failed to pass the final exams. 12. The patient was quite beyond the possibility of ______(recover). 13. Only by ______(acquire)a good knowledge of English can you do international business successfully. 14. Diamond necklaces and rings had been ______ (beauty) arranged on a background of black velvet. 15. However, I lost sight of Wang Ping when we reached ______ looked like a large market. 16. ______ rushed a tiger from among the bushes. As a result, a tourist was scared to death. 17. Unless ______(change), this law will make life difficult for farmers. 18.In China, especially in Shanghai, there was a time ______ many senior students wanted to study abroad. 19. Believe it or not, there is no such thing ______ standard English. 20. --- I saw no more than one motor car in that shop. Will you go and buy it? --- No, I’d rather find ______ in other shops.