The average teacher asks 350 questions a day. The kinds of questions asked fall into two categories: directed (also called "low-level") questions and open-ended (also called "high-level") questions. Of these 350 questions, most are directed.

By analyzing our own questioning techniques (e.g., how we ask questions, why we ask questions), we can find the balance between directed and open-ended questions that will most effectively encourage the development of higher-level thinking skills in our students.

Let's look more closely at the differences between directed and open-ended questions.

http://www.jetspost.com/eportfolio/pbl/driving_questions.htm

Centering things in Android...

android:gravity takes care of its children,
android:layout_gravity takes care of itself

https://alvinalexander.com/android/how-to-center-android-linearlayout-components-gravity