Cybermusings wrote:Birds' feathers appear to have evolved from dinosaur scales well over 100 million years ago, Chinese scientists have shown, based on a fossil bird found in the Yixian mountains of northern China.

A) Chinese scientists have shown, based on a fossil bird found in the Yixian mountains of northern China.

B) Chinese scientists have shown a fossil bird found in the Yixian mountains of northern China.

C) Chinese scientists showed, based on a fossil bird found in the Yixian mountains of northern China.

D) when the Chinese scientists found a fossil bird in the Yixian mountains of northern China.

E) which the Chinese scientists say can be proven from a fossil bird which they found in the Yixian mountains of northern China.

C is incorrect as it uses "showed". "have shown" is preferred.

D uses incorrect "when" changing the meaning of the sentence

E - again which cannot be used to refer to the action of the entire
clause preceding it

B uses 2 sentence fragments but not linked together.

A looks ok but the "Chinese scientists have shown" in the middle
of the sentence looks awkward.

Due to the lack of a better choice, I'm voting for A

OA please

U're right..OA is A....but why is shown preferred over showed?

"have evolved" --- "have shown"

This is a continuous action. So, present continuous is better than simple past

"have shown" is better than "showed"

Option B.
Chinese scientists have shown a fossil bird found in the Yixian mountains of northern China 'did not give a clear analysis of what why birds feather appear to have evolved from dinosaur.

Option C. Chinese scientists showed, based on a fossil bird found in the Yixian mountains of northern China.
'Chinese scientist showed' this is a past tense verb of what the scientist did but it is suppose to be stated with the verb 'have'

Option D. when the Chinese scientists found a fossil bird in the Yixian mountains of northern China.
'when' the adverb in an improper word to begin the next sentence of the statement.

Option E. which the Chinese scientists say can be proven from a fossil bird which they found in the Yixian mountains of northern China.
same as option D the adverb E cannot begin the second statement of the sentence