—________
A:They are my grandpa.
B:They are my grandma.
C:They are my grandparents.
-- I think your wife doesn't understand you.
-- On the c____, she understands me very well.
设数列an和bn的通项公式为an=15nn∈N*和bn=17nn∈N*,它们的前n项和依次为An和Bn,则limn→∞AnBn=( )
补全成语
①____声匿迹 ②物____天择 ③____然无存
④长途____涉 ⑤巧妙绝____ ⑥无动于____