помогите пожалуйста по английскому, заранее огромное спасибо

12. Put the verbs in brackets into the correct form (Past Simple or Past Perfect):
1 .The patient (to be) under medical care before the surgeon (to begin) the operation.
2.We (to complete) our observations on the changes in the blood erythrocytes by last
Wednesday.
3.Nobody (to investigate) this phenomenon before he (to do) it.
4.He (not to see) them in the classroom, because they already (to leave).
5.It (to be) clear, that something (to change).
6.On my way to the university I (to remember) that I (to leave) my report at home.
7.Where you (to work) before you (to enter) the university?
8.All my friends (to be) glad to hear that I (to pass) all the exarninations successfully.