I to phone her all day, but whenver I phone her, the line is engaged.
A. tried
B. had been trying
C. have tried
D. have been trying
网友回答
A. tried
B. had been trying
C. have tried
(答案→)D. have been trying
解析：从the line is engaged可得知与现在有关，排除AB，再从时间状语all day可知动作从过去开始一直持续到现在还很有可能持续下去，故使用现在完成进行时。句意：我一整天都在打她的电话，但是无论我什么时候打，电话都占线。