Выберите правильную форму глагола в соответствии с последовательностью времен
1I knew my friend (were waiting, are waiting) for me.
2Professor said that the law (had been, has been) discovered by the end of the 19th century.
3We were sure the new principles of higher education (wil be, would be) proclaimed in our country.
4The Dean said that the group (had passed, passed) all exams successfully.
5The mechanical theory of heat states that heat (is,was) a form of energy
6The scientist informed the conference that they (have been studying, had been studying) the phenomenon for several years.