Frank knows much about the city because he ______ there many times.( )
A.wentB.has goneC.has been
--- Can you tell me where Tom is? --- He ________ on the playground. A. plays B. playing C. is playing
-- _______ bad weather! -- So it is. A. What B. How C. What a
What _____ it is to go horse riding __________ weather!
________ great scientist Qian Xuesen is!
()I think _______ necessary for you _______ breakfast.