I’m going ____ train.A. by B. on C. At
—Excuse me, Jack. Where is the bus? —___________.
—What is thirty and twelve? —It’ s ___________.
—__________your brother here? —__________,he isn’ t here.
—__________the bike? —Look! It’ s under the tree.
Jim and I__________ students. We__________in the same class.