—______ there is no water left on the earth? —I really don’t know.
— What did you do on April Fool’s Day?— I played a trick _______ my brother.
For the first time, pay attention _________quickly to get the main ideas.
—I often make mistakes _______grammar.—Why not ask your teacher _______help?
Jenny used to be afraid ________ in class, so she always ________nothing.
________conversations with others is one of the secrets to ________a successful learner.