I at my new novel when the big earthquake happened at 2:20 pm.
A. am working
B. was working
C. have worked
D. had been working
网友回答
A. am working
(答案→)B. was working
C. have worked
D. had been working
解析：考查固定句式；固定句式：be doing sth when…正在做某事这这时…；本句中的when是一个并列连词“在那时”；句意：我正在写我的新小说，在这时在下午2:20发生了大地震；根据后面的happened，说明本句使用过去进行时。故B正确。