Long long ago,human beings held a dream that one day they could leave Earth and explore space.After many experiments,the scientists succeeded(1)
in
in
making rockets that could escape Earth's gravity and the(2)
impossible
impossible
(possible)dream came true.On 4 October 1957,the Sputnik 1 satellite(3)
was launched
was launched
(launch)by the USSR and successfully orbited around Earth.On 20 July 1969,American astronaut Neil Armstrong stepped onto the moon,(4)
saying
saying
(say),"That's one small step for [a] man,one giant leap for mankind. "
Although scientists tried to make sure nothing went wrong,some accidents still happened,which made everyone sad and disappointed.But the desire (5)
to explore
to explore
(explore)the universe never died. (6)
An
An
example of the ongoing exploration is the International Space Station.
China's space programme started later than those of Russia and the US,(7)
but
but
it has developed very fast.In 2003,China sent the Shenzhou 5 spacecraft into space(8)
independently
independently
(independent) .Then Shenzhou 6 and 7 completed a second manned orbit and the first Chinese spacewalk,(9)
followed
followed
(follow)by the vehicle Jade Rabbit being sent to the moon.More recently,China has sent Chang'e 4 to explore the surface of the far side of the moon to make measurements and observations.
Europe,the US,and China all have plans to further explore(10)
planets
planets
(planet)like Mars and Jupiter.Though there exist many difficulties,scientists hope that future discoveries will not only enable us to understand how the universe began,but also help us survive well into the future.