There's （a sign） on the wall.否定句、一般疑问句、提问

There's （a sign） on the wall.否定句、一般疑问句、提问
There's （a sign） on the wall.否定句、一般疑问句、提问

There's （a sign） on the wall.否定句、一般疑问句、提问
否定句 There is not a sign on the wall.
一般疑问句 Is there a sign on the wall?
提问 What is on the wall?

There isn't a sign on the wall
Is there a sign on the wall?
What is that on the wall?

There is not a sign on the wall.
Is there a sign on the wall?
What is this on the wall?

There isn't a sign on the wall.
Is there a sign on the wall?
What is that on the wall?