Ⅰ.用所给单词或短语的适当形式填空
light, none, discover, send back, think about
1．Please ____________ those things. I didn't order them.
2．All the children were very tired during the race, but ____________ of them wanted to give up(放弃)．
3．Have you ever ____________ becoming an astronaut?
4．Scientists ____________ many other galaxies in the universe already.
5．The sun gives out ____________ but we see it several minutes later.
