Question

—Oh, you have a headache and a cough. __________ have you been like this?
— Two days.

A．How long

B．How often

C．How old

D．How many

Answer 1

A

how long用来提问“多长时间”，对“一段时间的长短”提问时用，；how often用来提问某动作或状态发生的频率，对“一段时间内发生了几次活动”（always，usually， often， never或twice a day等表示频度的词或短语）提问时用。根据答语Two days知，上句问的应该是像这样的感冒有多长时间、多久了，故选A。