Question

She looked up at the stars. They were twinkling in the sky now.

     The stars…………………………………………………………………………………

Answer 1

The stars at which she looked up were twinkling in the sky now.

Answer 2

She looked up at the stars. They were twinkling in the sky now.

     The stars was looked up which were twinkling in the sky now.

Answer 3

Another answer. 

The stars which she looked up at were twinkling in the sky now.