What can we infer from the last paragraph？A．General relativity is actually ungrounded at a

Tom Murphy and his colleagues fire laser beams at reflectors on the moon with the aim to

A．measure the distance between the moon and the Earth.

B．calculate the speed of light.

C．check how long it takes light to cross it.

D．prove the equivalence principle more accurately.

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Galileo Galileis experiment at the Tower of Pisa around 400 years ago

A．was one way of testing Einstein"s general theory of gravity.

B．illustrated the insignificance of mass and composition of an object.

C．acted as a well-known example to testify the equivalence principle.

D．showed that all objects on Earth Were influenced by gravity.

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Scientists present at the "Rethinking Gravity" conference

A．unanimously believe that Einstein"s general theory of relativity is wrong.

B．have found further problems about the general theory of relativity.

C．question the assumptions of the general theory of relativity.

D．are trying to find out the possible flaws of the gravity theory.

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It is stated in Paragraph 1 that the theory of relativity

A．is beyond all the current scientists" understanding.

B．has failed Albert Einstein for years.

C．seems at odds with the quantum mechanics.

D．is useful in holding big things together.

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