Space vehicles were launched into outer space __________ search of another living planet.
举一反三
- Throughout the past few centuries there ______ recorded reports of space vehicles which have visited our earth from another planet. A: have been B: are C: had been D: were
- Why is the journey to the outer space not a dream any more? A: Because people can go anywhere now. B: Because people can travel to the outer space by airplane now. C: Because the modern means of transportation makes the journey smoother. D: Because people can travel to the outer space by rockets and space shuttles.
- Whether or not there is life in outer space is an enigma. We may never know for sure until we are capable of space travel or aliens actually land on our planet. What would we call something to which we have no answer? Enigma means () . A: reason B: certainty C: mystery
- The ( )of outer space is one of the greatest triumphs of modern science.
- Outer space ________________(not explore) by people 50 years ago.