Passage　3 
For　hundreds　of　years,　diseases　caused　by　lack　in　nutrition　(营养)　were　known　to　men.　Some　common　nutritional　diseases　are　beriberi　(脚气),　and　scurvy　(坏血病).　In　the　18th　century,　James　Lind,　a　Scottish　doctor,　discovered　a　cure　beriberi　-　whole　rice. 
A　British　scientist　in　1906　showed　that　certain　foods　contain　substances　important　to　the　growth　and　development　of　the　body.　In　time　these　substances　were　called　vitamins,　meaning　essential　to　life.　Today　there　are　13　known　vitamins.　The　human　body　produces　only　three　of　them. 
Vitamins　regulate　(调节)　the　way　the　body　changes　food　into　energy　and　living　tissues　(组织).　Each　vitamins　has　a　definite　use　and　the　lack　of　one　vitamin　can　interfere　with　the　function　of　another.　The　continued　lack　of　one　vitamin　can　cause　a　vitamin　lack　disease. 
The　best　way　for　a　healthy　person　to　get　vitamins　is　to　eat　a　balanced　diet.　Eggs,　milk,　meat,　vegetables,　fruits,　and　whole　-　grain　are　the　most　common　sources　of　the　necessary　variety　of　foods. 
Vitamins　help　to　speed　up　certain　chemical　reactions　in　the　body.　These　reactions　are　essential　for　health.　Without　vitamins,　these　reactions　would　occur　very　slowly　or　not　at　all. 
Truly　vitamins　have　been　correctly　named　-　essential　to　good　health　and　life. 
11.　Men　have　know　about　nutritional　diseases　__________. 
○A.　a　long　time 
○B.　in　18th　century 
○C.　recently 
○D.　in　1906 

12.　Beriberi　is　a　type　of　_________. 
○A.　food 
○B.　vitamin 
○C.　fruit 
○D.　disease 

13.　It　takes　scientists　_______　to　know　how　many　vitamins　there　are. 
○A.　a　long　time 
○B.　a　few　years 
○C.　a　short　time 
○D.　a　number　of　experiments 

14.　Human　body　produces　__________　kinds　of　vitamins. 
○A.　all　kinds　of 
○B.　five 
○C.　thirteen 
○D.　three 

15.　Eating　_______　is　the　best　way　to　get　vitamins. 
○A.　few　things 
○B.　vegetables 
○C.　fruits 
○D.　many　kinds　of　food