如图，在平面直角坐标系中，以O为圆心，适当长为半径画弧，交x袖于点M，交y轴于点N，再分别以点M、N为圆心，大于MN的长为半径画弧，两弧在第二象限交于点P．若点P的坐标为（2a，b+1），则a与b的数量关系为（　　）

如图是某摄影师抓拍的一滴水珠下落到水面瞬间的照片，水珠后方的人通过水珠成____ 、缩小的实像，此时水珠相当于____ 镜；水珠在水中所成的像是____ 像（选填“虚”或“实”），此时水面相对于____ 镜．

    Stephen Hawking is one of the most famous scientists in this century. The disabled writer of A Brief History of Time, was on his second journey to China in Hangzhou of Zhejiang Province. His first 1was over ten years ago. The great theoretical scientist has been invited to 2 a mathematics research institute at Zhejiang University, Metropolis Newspaper reported.3Sunday evening, he made his appearance at a press conference 4 at Shangri-La hotel, Hangzhou. Hawking 5 at about 5: 00 pm with his wife. The elderly man answered a total of nine 6 with the help of his 7. “I find the real universe much more 8 than the one in the film Star Wars,” Hawking joked. “I 9 young people to study theoretical physics first 10 they are interested in it. But the talented man 11 has produced such rich work suffers from 12 motor neuron disease（运动神经元病）. He is one of the 350,000 sufferers in the world. The disease 13 over 100,000 people every year. “I like life and I love life, my family ,and music give me the 14 happiness,” smiled Hawking, who can 15 move two fingers.

    In the speech, Hawking said he was 16 to write a new edition of A Brief History of Time 17 young children. “A Brief History of Time is my first book for 18 people. But I later found that I could write it in a 19 way,” he answered. “So I decided to rewrite it 20 all people can read it easily.” Unfortunately, he left us forever on Marchl4 this year. We remember his words “My goal is simple. It is a complete understanding of the universe, why it is as it is and why it exists at all.”

随着数字时代的到来，3G与4G的相继出现，现在我们已经可以很方便的使用3G或4G手机进行无线网络登陆．下列对手机上网的说法中，正确的是（  ）​