OFFICIAL EXPLANATION
So far, no pieces of evidence pointing to extraterrestrial life have been found.A. So far, no pieces of evidence pointing to extraterrestrial life have been found
This answer choice correctly uses the Present Perfect with the time expression So far, as it denotes a continuous action which has begun in some indefinite time in the past and has continued until the present.B. So far, no pieces of evidence pointing to extraterrestrial life were found
Incorrect.
This answer choice is grammatically incorrect. It incorrectly uses the Past Simple (were) with the time expression So far. So far is indicative of the Present Perfect because it indicates that the action described began in the past and continues to the present.C. So far, no pieces of evidence pointing to extraterrestrial life are found
Incorrect.
This answer choice is grammatically incorrect. It incorrectly uses the Present Simple (are) with the time expression So far. So far is indicative of the Present Perfect because it indicates that the action described began in the past and continues to the present.D. No pieces of evidence pointing to extraterrestrial life are being found, so far
Incorrect.
This answer choice is grammatically incorrect. It incorrectly uses the Present Progressive (are being) with the time expression So far. So far is indicative of the Present Perfect because it indicates that the action described began in the past and continues to the present.E. No pieces of evidence pointing to extraterrestrial life had been found, so far[/quote]
Incorrect.
This answer choice is grammatically incorrect. It incorrectly uses the Past Perfect (had been) with the time expression So far. So far is indicative of the Present Perfect because it indicates that the action described began in the past and continues to the present.