A particular rocket car can travel for sustained periods at a maximum speed of 240 miles p
A.2.8
B.18 1/2
C.21 1/2
D.22
E.24
A.2.8
B.18 1/2
C.21 1/2
D.22
E.24
火箭电泳(rocket electrophoresis or rocket immtmoelectrophoresis)。
Up ______ into the air when the ten-second countdown was over.
A.the rocket shot
B.shot the rocket
C.was the rocket shot
D.the rocket was shot
______ reported the rocket attacks.
A.Two hospitals
B.Local newspapers
C.A news agency
D.Leaders of the main factions
A.The rocket should be inexpensive to construct.
B.The rocket is capable of lifting heavy spacecraft into orbit.
C.The rocket should be easily controlled.
D.The rocket should be inexpensive to operate.
The higher a rocket flies, ______air it meets.
A.the fewer
B.the little
C.the less
D.the much
What does "an earthbound rocket" in Sentence 3 Para. 3 mean?
A.A rocket sent from the earth to the moon.
B.A rocket sent from the moon to the earth.
C.A rocket made of earth.
D.A rocket with no purpose.
According to the passage, the most difficult task of firing a rocket is ______ .
A.to get the rocket into the space
B.to calculate the rocket's velocity of escape
C.to guide the rocket after it leaves the Earth's surface
D.to identify the gravitational fields of the Earth and the moon
Generally speaking how many stages are there in a multistage rocket?
A.Two.
B.Three.
C.Four.
D.Five.
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