---What do you usually do when it is raining?---I often TV. A. are watchingB. watch C. wa

问题补充：

---What do you usually do when it is raining?

---I often TV.

A. are watching

B. watch

C. watches

D. watching

答案：

A. are watching

(答案→)B. watch

C. watches

D. watching

解析：句意：当下雨时，你通常做什么？——我常常看电视。结合语境可知下文描述的是反复性的动作，故用一般现在时态。主语I是单数第一人称，故谓语动词用原形，选B。