求助道语法

Twenty-two feet long and 10 feet in diameter, the AM-1 is one of the many new satellites that is a part of 15 years effort of subjecting the interactions of Earth’s atmosphere, oceans, and land surfaces to detailed scrutiny from space.

A.      satellites that is a part of 15 years effort of subjecting the interactions of Earth’s atmosphere, oceans, and land surfaces

B.       satellites, which is a part of a 15-year effort to subject how Earth’s atmosphere, oceans, and land surfaces interact

C.      satellites, part of 15 years effort of subjecting how Earth’s atmosphere, oceans, and land surfaces are interacting

D.      satellites that are part of an effort for 15 years that has subjected the interactions of Earth’s atmosphere, oceans, and land surfaces

E.       satellites that are part of a 15-year effort to subject the interactions of Earth’s atmosphere, ocean, and land surfaces
        

  我选的是D.

答案是E. 不明白的是,ocean为什么用单数?

还想问下各位大侠,being的用法,是不是用在开头都是错的?

ocean应该等于oceans,求证,建议不要将此作为区别点.

being用在开头不一定都是错的. 一般情况下其出现即很可能为错,但有特例,建议结合其他语法点综合来排除.