为你解答.
问:Was there a highway 50 years ago?
答:No, (there wasn't.) But (there used to be) a (road).
(句意:50年前有一条公路吗?没有,但有一条路.
问:Is the city different now?
答:Yes. Now (there is)a (subway) and lots of (modern buildings).
(句意:城市的面貌现在不一样了吗?对,现在有地铁了,还有许多现代化的楼.)