[简答题]Currently, rules on using these devices are left up to individual airlines.

[简答题]Currently, rules on using these devices are left up to individual airlines.

[填空题]

Using the U.S. space agency’s NASA Chandra X-ray ______, Alexey Vikhlinin and his colleagues observed 86 tightly-packed ______ clusters.

[单项选择]A) He enjoyed using his new camera.
B) He left his camera at the airport.
C) He left his camera in his friend’s car.
D) He lost his camera on his trip.

[填空题]Using a new{{U}} (36) {{/U}}device called Microwave Landing System (MLS) , airplanes will be able to land themselves. With MLS, more planes will be able to land on the ground more quickly and more safely without a pilot’s touching the controls. From the time a plane enters the zone of area covered by MLS until it lands, it is controlled com plctcly and{{U}} (37) {{/U}}Bad weather has no effect on the system, even zero{{U}} (38) {{/U}}fog. The normal operations for landing—engine reversal,{{U}} (39) {{/U}}, and steering—are{{U}} (40) {{/U}}by MIS. The pilot does not have to do anything; however, the pilot may take control again if the need{{U}} (41) {{/U}} Using the current{{U}} (42) {{/U}}Landing System(ILS) ,pilots follow a radio beam. The ILS beam is very narrow, like a long tube. To follow it, airplanes must fly{{U}} (43) {{/U}}along the beam, starting at least eight kilometers from beginning their approach to touchdown. In many cases, pilot must begin t

[填空题]下面程序的输出结果是〈u〉 【9】〈/u〉。
#include 〈iostream〉
using namespace std；
void f(int x)

if(x)

cout．put(’0’+x%10)；
f(x／10)；


int main（　）

f(11001)；
return 0；

[填空题]The U.S. Rubber Company is making tests of using the elastic skin of a dolphin for beats and submarine hulls.