Since the start of the space age, more and more littering has occurred in orbits near Earth, often because the intentional discarding of lens caps, packing material, fuel tanks, and payload covers.
Since the start of the space age, more and more littering has occurred in orbits near Earth, often because the intentional discarding of lens caps, packing material, fuel tanks, and payload covers.
A more and more littering has occurred in orbits near Earth, often because
B orbits near Earth have become more and more littered, often from
C orbits near Earth became littered more and more, often resulting from
D there have been more and more littering of orbits near Earth, often because of
E there had been littering more and more of orbits near Earth, often with
B选项there have..... littering of orbits 主谓一致问题。 littering of orbits应该是单数谓语
若littering是名词的话,但是我查了半天也没有看到littering是名词啊,估计是litter的gerund形式。但是litter本身还是名词,若用名次用法,单独litter就够了,不用littering。