Ex.8. Insert the present indefinite passive, the presentcontinuous passive, the present perfect passive.1.Each chapter of thebook is written by a different person.2. The rise is fairly and maximumlevel is being reached in about two hours.3. The term is being used now to mean guite adifferent phenomenon.4. High-speed industrial methods has been used inbuilding.5. The following hypothesis is presented for discussion.6. SinceThomas Young it has been recognized that normal human colour vision istrivariant.7. In the past few years significant progress has been made inanswering some of these guestions.8. The research undertaken in theirlaboratory a year ago is being completed now .9. These phenomena is also influenced by lattice effects.10. The dimensions of the solar system are determined by the extreme orbit of Pluto which is slightlyelliptical.11. Experimental observations are now being made with a view toestablishing certain facts.12. No material basis is now being provided for suchextensive studies.13. Even this problem hasn't been solved yet. Такое ощущение, что все это сочинял русскоговорящий товарищ, довольно странная лексика и времена странно употребляются. Надеюсь, мне удалось понять логику автора)