题目

I haven’t seen Ann for ____ long that I’ve forgotten what she looks like.A. such                     B. very                        C. so           D. too 答案：C解析so…that…“如此……以致……”,引导结果状语从句。so后跟形容词或副词，such后跟名词。已知数列{an}满足a1=1，且（n+1）an+1=nan，则数列a2012的值为（ ）A．2011B．2012C．D．