Have you ever wondered what dolphins are really like? As it turns __21__ they are actually amazing creatures.
Dolphins have tremendous maneuverability, in part because of their muscles and fins. The front fins work a lot like wings on an airplane by helping it glide through the waters. At the same time, the __22__ acts like a propeller.
Dolphins also gain an __23__ because of their intelligence. Dolphins are one of the most intelligent creatures on the planet. Another thing __24__ gives dolphins and advantage is their social behavior. Dolphins live in groups called pods. If one of the dolphins in a pod __25__ sick or injured, the others will do their best to help out. 【題組】22. (A) tail (B) arm (C) blade (D) wheel