1. She sat (или was sitting- здесь возможны варианты!) in the library, studying up on issue cultures as an aid to further practical
work in the laboratory
2 .Ted had been helped in setting her up with some relatively harmful viruses so that she could get familiar with the latest virology equipment.
3. Melissa checked her watch. At three she had an appointment with her boss.
4. The day before she gave his secretary a formal request for permission to use the laboratory, outlining the experimental work she wanted to do.
знаете, а глагол был только в первой скобке!... проверьте само задание,а? ну, на всякий случай...