若$a>0,b>0$且$a+b=4$,则下列不等式恒成立的是    （）

蛋白质是构成细胞的基本物质，下列食物中富含蛋白质的是（　　）

“别人与我比父母，我与别人比明天”是一群农民工子女震撼亿万人心的呐喊。农民工子女的呐喊体现的是（    ）

①嫉妒心         ②自信心   ③自弃心理    ④自强品质

阅读理解

    “Billy, one, two, three, get up! It is 25^th February, 2099, seven' o'clock．It's time to get up and go to school, ”says the clock-robot in a loud voice．Then the clothing—robot dresses(给……穿衣服)Billy quickly．Next the kitchen—robot gives Billy some bread and eggs.  Billy doesn't like them, and the kitchen—robot gives him a hamburger．After eating the hamburger, Billy goes to school．When he gets out of the house with his schoolbag, he sees a car-robot waiting for him．“Hello! I will drive you to school．Your name is Billy, isn't it?” asks the car．“Right．”Billy answers．“Now would you please show me your school ID card?” says the car．Billy shows it his school ID card．“Get in, please．”Billy gets in it．Then the car goes on, “l will check your homework today．Please take it out．”Billy does as what the ear-robot says．When they get to school, the car says to Billy, “See you tomorrow, Billy．Good luck!”

南极地区泛指（　　）​