【简答题】Laudenslager’s experiment showed that the immune system of those rats who could turn off the electricity ________. A) was strengthened B) was not affected C) was altered D) was weakened
【单选题】Assuming that the engineering problems could be overcome, the production of a time machine could open up a Pandora's box of causal paradoxes. Consider, for example, the time traveler who visits the pa...
A.
the time machine in the future would be feasible
B.
the time machine in the future is just like the Pandora's ox