31.By 9p.m last night, our group _________ the assignment on the environment. A. submitted B. had submitted C. has submitted D.was submitted Mark the letter A, B, C or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions. 32 . Because of the flood happened, many families lost their houses. A . Because of B . flood C . families D . houses Mark the letter A, B, C, or D to indicate the correct question for the underlined parts in each of the following sentences. 33. Earthquakes and volcanoes have caused most of the natural disasters in that country. A. Most of the natural disasters have been caused by earthquakes and volcanoes in that country. B. Most of the natural disasters in that country has been caused by earthquakes and volcanoes. C. Most of the natural disasters in that country have been causing by earthquakes and volcanoes. D. Most of the natural disasters in that country have been caused by earthquakes and volcanoes. 37. I like listening to music, but I like playing football more. A. I prefer playing football than listening to music. B. I prefer to play football to listen to music. C. I like listening to music more than playing football. D. I prefer playing football to listening to music. Giải thích tại sao