完形填空

　　Today is Sunday. Mike and Peter 1 go to school. Listen! They are talking about the life  2 in the room." 3 will the world be like? "Peter asks."I think that the world will be a 4  place to live in. And we will 5 machines and robots at home. They will help us do lots of 6  , "says Mike. "The robots will help  7 cook dinner, clean the houses and  8 old people. I think there will be a kind of medicine(药)  9  it can make us live more than 100 years, "Peter says."What will you do then? "says Mike."Then I will  10  my great-grandchildren(曾孙)to the moon, "says Peter. "The moon? I will go to the Mars(火星)with my wife, "says Mike.

如图所示的电路中，电源的电动势E和内阻r恒定不变，滑片P在变阻器正中位置时，电灯L正常发光，现将滑片P向右移动，则 （       ）

We can't afford _____ such a high price .