用方框中所给短语的适当形式填空
space travel, have been to, work hard,
a group of, by spaceship
(1)
people have seen a UFO already.
(2)
and you'll make it.
(3)
Ithe Summer Palace before.
(4)
You can travel far enough.
(5)
I'm going to haveto Mars one day.
答案: 【1】A group of
【1】Work hard
【1】have been to
【1】by spaceship
【1】space travel