—Dad, when shall we go to visit my grandpa?
—Grandpa is very busy at present．We'll go to see him whenever .
A. he is convenient
B. he will be convenient
C. it is convenient to him
D. it will be convenient to him
网友回答
A. he is convenient
B. he will be convenient
(答案→)C. it is convenient to him
D. it will be convenient to him
解析：首先，若用convenient表示“某人方便”之意，绝对不能使用人作主语，而应使用it，由此排除A、B选项，类似地，possible等形容词也不能以人作主语，应使用it作主语。此外，由whenever引导的时间状语从句遵循的是“主将从现”原则，由此判断答案为C