[問題]考古form35- Q11

[kaijen]

The lack of complete historical records from the mid-to-late 1800's have made some Black inventions difficult to trace to their originators.

(A)have made some Black inventions difficult to trace to their originators
(B)have made for difficulties in tracing some inventions by Blacks to their originators
(C)have made it difficult to trace some inventions by Blacks to their originators
(D)has made it difficult to trace some inventions to their Black originators
(E)has made it difficult in tracing some Black inventions to their originators

Ans:(D)
請問:
1.(E) make it difficult in Ving 符合慣用語嗎?
2.(D)(E)their 是指inventions還是黑人? 感覺(E)比較好耶??