Ⅰ.用适当的连词填空
1.(2015·安徽改编) scientists have learned a lot about the universe,there is much we still don’t know.
2.(2015·重庆改编)If you miss this chance,it may be years you get another one.
3.(2015·陕西改编)I believe you will have a wonderful time here you get to know everyone else.
