目前认为，与人类龋病关系最密切的微生物为（）
A.血链球菌
B.酵母菌
C.变形链球菌
D.放线共生放线菌
E.韦永氏菌
参考答案：C
Something is wrong with my _____. I can't see anything around me. [ ]
A. nose
B. ears
C. eyes
D. mouth
Mount Qomolangma is ____ mountain in the world. [ ]
A. high
B. higher
C. much higher
D. the highest
