The research lacks  evidence, and therefore, its conclusions are doubtful.

So many years have passed and the terrifying accident is still ______in her mind.

 Whenever a patient needs an injection of Penicillin, the doctor does need to make sure whether his patient is ___ to the medicine.

．After a long walk, the little boy got home at last, ________.

It was a really_____experience. Afterwards everybody was very_____ .