I wonder why they’re so late. They ______ here an hour ago.
He asked several questions_______ the professor who gave us a lecture_______the balance of nature.
We thought of selling this old furniture, but we’ve decided to _____ it. It might be valuable.
I’m not very good at playing chess. He often _______ me.
Mrs. Black doesn’t believe her son is able to design a digital camera, ________?
--How is_______ going with you? -- So so.