A．has been conceivedB．had been conceivedC．have been conceivedD．were conceived
A. has been conceived
B. had been conceived
C. have been conceived
D. were conceived
查看答案
A．adaptB．have adaptedC．adoptD．have adopted
A. adapt
B. have adapted
C. adopt
D. have adopted
Whether we realize it or not(Para. 3), "it" refers ______.
A. weightlessness
B. the continuous and universal nature of gravity
C. the fact that our bodies never forget
D. the previous statements
The tree was cut ______.
A. down
B. in
C. off
D. ont
According to the passage we do not perceive gravity because ______.
A. we live in a downward-pulling world
B. there is no decrease or increase force of gravity on our bodies
C. our senses provide accurate information about the location
D. our brains integrate signals from all apparatus of the body
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