Перепишите предложения, подчеркните сказуемое главного предложения и определите видо-временную форму и залог глагола. (Например, was going – Past Continuous Active от глагола to go).
1 Botanical prospecting has been used in the search for deposits of ores.
2 Men have been curious about the mysterious underwater world for centuries
3 Scientists began serious research in this field only in our time.