问题补充：
--- students are there in your class?
--- Thirty-five.
A. How old
B. How much
C. How many
D. How often
答案：
A. How old
B. How much
(答案→)C. How many
D. How often
解析：A. How old多大年龄了？B. How much多少，修饰不可数名词；C. How many多少，修饰可数名词的复数形式；D. How often多久一次，表示频率；句意：在你们班有多少名学生？35名。故选C.
