题目

It's getting _______ for young people to wear sunglasses in summer this year.A.scary B.interesting C.difficult D.popular 答案：【答案】D【解析】句意：今年夏天，年轻人戴太阳镜很流行。考查形容词辨析。scary可怕的；interesting有趣的；difficult困难的；popular受欢迎的，流行的。根据空后“…for young people to wear sunglasses in summer”和常识可知，年轻人在夏天戴太阳镜变得很流行。故选D。已知数列{an}满足：①a2＞0；②对于任意正整数p，q都有ap•aq=2p+q成立．（I）求a1的值；（II）求数列{an}的通项公式；（III）若bn=(an+1)2，求数列{bn}的前n项和．