完形填空 Vitamins(维生素)  are a discovery of the 20th century. A hundred years 1 , no one knew anything 2 them. The vitamins are 3 by letters of alphabet. Vitamin A 4 by the eyes. There is vitamin A in milk, butter and green vegetables It 5 by the body. Vitanun B must be supplied (提供) 6 by some of our food. The skins 7 grains of all sorts have vitamin B in them. Vitamin C is very important 8 _ the body. Without it 9 teeth will become loose and their arms and legs become weak. Oranges and tomatoes 10 vitamin C in them. There are other vitamins.  But these A, B,C are the most important. (     )1. A. before (     )2. A. about (     )3. A. naming (     )4. A. needs (     )5. A. stores (     )6. A. times (     )7. A. of (     )8. A. in (     )9. A. people (     )10.A. has B. front B. of B. named B. need B. be stored B. in not time B. to B. at B. peoples' B. have C. ago C. in C. is named C. is needed C. can store C. all the time C. on C. with C. people's C. there is D. ahead D. for D. names D. was needed D. can be stored D. any times D. in D. to D. peoples D. there are