Укажите предложения с модальными глаголами, выражающими необходимость совершения действия. Переведите.
1. As telegraph wires couldn't be hung over the ocean, cables had to be laid on the floor of the Atlantic Ocean. 2. In the next few years engineers are to develop computers of more than 2 billion operations a second. 3. A new kind of telephone may be called a video-phone. 4. One must know that we shall need a lot of specialists that will be able to work and live in space for a long time. 5. To see distant objects clearly, one should change the focus. 6. Within a few coming years a quantity production of various materials is to begin in space. 7. Some liquid mixture components would immediately separate on Earth because of different density. 8. It should be said that special space vehicles are necessary for industrial production of space materials. 9. Our group will be allowed to use new laboratory equipment next term. 10. One can see that there is no principal difference between iron and copper as conductors.

2are to
4must
6is to

5,8 should, переводиться как должен в значении -следует,даётся совет.не уверена за эти два.