单项选择题
When Mike Kelly first set out to build his own private space-ferry service,he figures his bread-and-butter business would be lofting satellite into high earth orbit.Now he thinks he may have figured wrong.’People were always asking me when they could go,’says Kelly,who runs Kelly Space Technology,’I realized the real market is in space tourism.’According to preliminary market surveys,there are 10,000would-be space tourists willing to spend $1million each to visit the final frontier.Space Adventures in Arlington have taken more than 130deposits for a two-hour,$98,000space tour tentatively set to occur by 2005.This may sound great,but there are a few hurdles:Putting a simple satellite into orbit--with no oxygen,lift:support or return trip necessary—already costs an astronomical $2,200/kg.And that doesn’t include the cost of insuring rich and possibly litigious (爱打官司的)passengers.The entire group of entrepreneurs trying to comer the space-tourism market has between them ’just enough money to blow up one rocket’.The U.S.space agency has plenty of money but zero interest in making space less expensive for the little guys.So the little guys are racing to do what the government has failed to do:design a reusable launch system that’s inexpensive,safe and reliable.Kelly Space’s prototype looks like a plane that has sprouted rocket engines.Rotary Rocket in California has a booster with rotors to make a helicopter-style.return to earth.The first passenger countdowns arc still years away,but bureaucrats at the Federal Aviation Administration in Washington arc already informally discussing flight regulations.After all,you can’t be too prepared for a trip to that galaxy far,far away.
Which of the following is the best title for the passage?()
A.Take Vacations in SpaceB.Building Hotels in SpaceC.Flight Regulations in Space TravelsD.Cost of Space Traveling
单项选择题 函数f()、g()的定义如下所示,调用函数f时传递给形参x的值为5,若采用传值(call by value)方式调用g(a),则函数f的返回值为(1);若采用传引用(call by reference)方式调用g(a),则函数f的返回值为(2)。A.14B.16C.17D.22
多项选择题 特种设备作业人员的安全生产义务主要有()。
单项选择题 根据下列材料,请回答下列各题:男性,49岁。右侧胸痛、干咳2周就医。体检:气管居中,右胸叩浊,呼吸音消失。x线胸片示右侧大量胸腔积液,胸腔积液为血性,找到癌细胞,大致为腺癌。从胸部X线平片上下列哪种征象应考虑到肺癌可能