gwd31-28

GWD-31-Q28
Rock samples taken from the remains of an asteroid about twice the size of the 6-nuke-wide asteroid that eradicated the dinosaurs has been dated to be 3.47 billion years old and thus is evidence of the earliest known asteroid impact on Earth.
A: has been dated to be 3.47 billion years old and thus is
B: has been dated at 3.47 billion years old and thus
C: have been dated to be 3.47billion years old and thus are
D: have been dated as being 3.47 billion years old and thus
E: have been dated at 3.47 billion years old and thus are
这道题答案E...

两个差别就在于dated to be 和at，我用goole查了一下，两种都有好多例句……请大家帮忙确定一下吧……谢谢了

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