Had it been possible, I would have gone to attend Monica in the hospital, but I fully occupied last month.
A. had been
B. was
C. am
D. have been 过去相反，
网友回答
A. had been
(答案→)B. was
C. am
D. have been 过去相反，
解析：考查时态。But后面的句子使用陈述语气，要根据前面的虚拟语气的形式确定后面的时态。如果前面表示与过去相反，那么后面就使用过去时。如果前面前面表示与现在相反，后面就使用现在时。本题前面使用了would have gone,这是一个表示与过去相反的虚拟语气，故后面使用过去时。故B正确。