Перепишите предложения, переведите их, обращая внимание на употребление формы Per fect (Present, Past) в действительном и страдательном залогах.

1) Scientists have found ways of measuring the sizes and positions of bodies in the Universe. 

2) A primitive steam-engine had been invented by Thomas Newcomen at the beginning of the 18th century.

3) Our family hasn't heard from him for 5 months.