Scientists have not always been widely praised.
ADVERBS THAT DESCRIBE THE PARTICIPLE TO SAY "HOW" OR "HOW MUCH" OFTEN GO BEFORE IT.
Some have even been sharply criticized.
Liquid water has not yet been found on Mars.
STILL GOES AFTER HAS / HAVE / HAD. IN NEGATIVE STATEMENTS, YET GOES AFTER NOT OR AT THE END OF A CLAUSE.
The difficulties of research had not always been understood.
Some progress clearly has been made. (more emphatic)
Liquid water has still not been found on Mars.
ADVERBS USUALLY GO AFTER HAS / HAVE / HAD. SOME CAN ALSO GO BEFORE FOR EMPHASIS. IN NEGATIVE STATEMENTS, ADVERBS USUALLY GO AFTER NOT.
Liquid water has not been found on Mars yet. (less formal)
Some progress has clearly been made
