DM
Dasha Maslikova
Помогите найти глагол-сказуемое и определить его видо-временную форму и залог
1.The problem of the structure of matter is constantly occupying the minds of many scientists.
2.Professor N. was being listened to with great attention.
3.Now everything is being done to make the experiment in time.
4.Today scientists are still looking for the substance as a source of energy.