do you watch TV every day?---For about half an hour.A. What timeB. WhenC. How longD. H

问题补充：

--- do you watch TV every day?

---For about half an hour.

A. What time

B. When

C. How long

D. How many

答案：

A. What time

B. When

(答案→)C. How long

D. How many

解析：What time什么时刻； When什么时候；How long多长；How many多少个。根据下文，大约半小时。可知上文提问时间长久，故选C。