单选题 The student ______ continuing his studies when he had to return to his home country unexpectedly.
A. is considering B. was considering C. should consider D. has considered

【正确答案】 B
【答案解析】[解析] 过去进行时用法
本句中，when引导的时间状语从句为过去时，所以主句应为过去时，故可排除其他三项。根据语意，这位学生在过去的那个时刻正在思考是否继续求学，所以用过去进行时。B项符合。