21. Iran’s first nuclear power plant started supplying electricity to the national grid on Saturday, ____ on stream after years of delays, Iran’s ISNA news agency reported.
A. to come B. come C. having come D. coming
22. Across North China _____ in the world, namely the Great Wall.
A. the longest wall runs B. runs the longest wall
C. does run the longest wall D. does the longest wall run
