Astronomers estimate called the Pleiades in the constellation Taurus is 415 lightyears away from Earth.
A.that a loose cluster of stars B.a loose cluster of stars is
C.that is a loose cluster of stars D.there is a loose cluster of stars
Astronomers estimate called the Pleiades in the constellation Taurus is 415 lightyears away from Earth.
A.that a loose cluster of stars B.a loose cluster of stars is
C.that is a loose cluster of stars D.there is a loose cluster of stars
A
estimate是及物动词，后面的空格应该是宾语，或者宾语从句。A项从句的谓语是后面的is。B、C、D三项的谓语和后面的谓语矛盾了，一个句子只能有一个谓语。