几道简单的英语选择题、填空题

几道简单的英语选择题、填空题
1.Nothing is difficult in the world if you set your m__（以m开头的）to do it.
2.-Would you mind watering the flowers for me?
-( ).I have to go to the post office.
A.Not at all B.Never mind
C.No,please D.Sorry,I can't
3.We ( )talking until late into the night and enjoyed ourselves.
A.went on B.put on C.help on D.bagan on
可以每道题后面跟一点注解,