SAT几道改错题求助At the age of seventy-one,legendary country music artist JC astonished his fans by performing a song that the rock group Nine Inch Nails orginally (has recorded).为什么has recorded 错了?怎么改?Today in class we discussed the common,but mistaken,assumption that when two people are no longer dating they are incapable (to be )friends.为什么to be 错了?怎么改?A great gray owl (flying low) across a forest clearing,its (wings beating) quietly and its ultrasensitiv

SAT几道改错题求助
At the age of seventy-one,legendary country music artist JC astonished his fans by performing a song that the rock group Nine Inch Nails orginally (has recorded).
为什么has recorded 错了?怎么改?
Today in class we discussed the common,but mistaken,assumption that when two people are no longer dating they are incapable (to be )friends.
为什么to be 错了?怎么改?
A great gray owl (flying low) across a forest clearing,its (wings beating) quietly and its ultrasensitive ears turned to the faint sounds made by smalll creatures concealed under leaves.
我觉得wings beating 错了,beating 应该改成beat才能和and后面平行,为什么答案写的是flying low错了?
（Determined to) make a name for herself as a writer of short stories,Helen never submits anything to an editor until (revising) it several times.
我选的是determined to,为什么错的是revising?determined 不应该改成determing么?