—How long have you been like this?— .ALast month B．Two months ago C．Since last month

问题补充：

—How long have you been like this?

— .

A．Last month B．Two months ago C．Since last month

答案：

解析：考察时间状语。Last month上个月；Two months ago两个月前；Since last month自从上个月以来。根据上文，你这样多久了？since last month与现在完成时连用，AB与一般过去时连用，故选C