How long do you think it will be ______ another e-commerce giant comes out to exceed Alibaba?
Mr. Green showed his students some photos ________ at World Expo 2010 Shanghai.
A group of children are looking into the box, ____ about what can be inside.
I must be off now. My friends ________ outside.
David is a great teammate. He knows well how to work with __________.
I was about to walk over to Tom’s seat when he ____ and left.