12.2.3 Subjunctive mood. Replace the infinitive in brackets by the correct form.

Taking in to account Phobos gravity, if an astronaut threw the stone, it (to orbit) the entire moon. So, now, exploring Phobos (to be) a difficult problem because if its small gravity field. If the orbit were parallel with the equator, the satellites (to make) to stay permanently over a particular point on the surface. It is important that the pilot of a high-speed aircraft (to know) how near his aircraft is to the sound barrier. He ordered that the children ( to get up) at 7 o’clock. If all submersibles had had autonomous principle of operation (to become) much more useful. The accuracy of the system would be improved if signals (to transmit) on two frequencies simultaneously. It is essential that international cooperation (to be) as productive as possible.


Решение: 12.2.3Решение: 12.2.3Решение: 12.2.3