21. The Romantic poets were very interested in ____ nature, and often used it as ___ theme in their poetry.
A. a; the B. the; a C. 不填; a D. a; 不填
22. China _____ its success _____ the reform and opening-up policy and the leadership of the Communist Party of China．
A．owes; to B．thanks; for C．bases; on D．relies; on
