大全补充题140

140. It may be another fifteen years before spacecraft from Earth again venture to Mars, a planet now known to be cold, dry, and probably lifeless.

(A) again venture to Mars, a planet now known to be

(B) venture to Mars again, a planet now known for being

(C) will venture to Mars again, a planet now known as being

(D) venture again to Mars, a planet that is known now to be（A）

(E) will again venture to Mars, a planet known now as being

为什么不能选D?  谢谢！

a planet...lifeless, 是作Mars的同位从句，D 不够简洁。

不知评论对否，烦请nn comment.

再补充一点，Ｄ中again 的位置改变了，again Ａ用于强调venture,but in D,it modifies to mars