Russian and American scientists are working together to solve the problem of motion sickness in astronauts.
A. Right
B. Wrong
C. Not mentioned
A.broughtB.takenC.designed D.protected
A. brought
B. taken
C. designed
D. protected
A.abilityB.service C.systemD.channel
A. ability
B. service
C. system
D. channel
Pilots flying at the height of more than 2,100 meters saw a thick black column of
A. Right
B. Wrong
C. Not mentioned