Hello native English speakers. Which of the following expressions is grammatically correct? Which one is a noun phrase? Which one is a complete sentence? 1. The thing which you think will happen in the future. 2. The thing you think will happen in the future. (= The thing that you think will happen in the future?) 3. What you think will happen in the future. 4. The thing that you think will happen in the future. (I guess only number 1 is a noun phrase?)