(2013·安徽卷)From space, the earth looks blue. This is about seventy-one percent of its surface is covered by water.
It’s getting late. We must "be off" now. Which of the following can’t replace the underlined part?
----- The flower is beautiful. ----- _________.
----- Are you going there with them? -----If you go, ________.
There is _____ a pen, an eraser and some pencils in her pencil-box.
----- Is she a teacher? ------ Yes, _____.