----has Tom been a doctor ?---Since two years ago.A. How soonB. How muchC. How manyD. H

问题补充：

----has Tom been a doctor ? -----Since two years ago.

A. How soon

B. How much

C. How many

D. How long

答案：

A. How soon

B. How much

C. How many

(答案→)D. How long

解析：句意：汤姆当医生有多久了？自从两年前就是医生。A多久以后B多少，问价钱C多少，提问可数名词复数，D多久，故选D。