Dolphins are known as cetaceans, or marine (12)_____: they breathe air, they are warm blood, and they bear live young ones called (13)_____ The size of dolphins varies greatly. The smallest dolphin is just about 50 kg in weight and 1.2 meters in length (14)_____ the largest one can weigh up to 8.200 kg and is 10 meters long. Dolphins are sociable creatures. They swim together in group known as schools. They show great ability in the water and you can often (15)_____ them playing (16)_____ ships.
Câu 12: A. fish B. creatures C. mammals D. life
Câu 13: A. babies B. calves C. young D. diets
Câu 14: A. when B. as C. while D. since
Câu 15: A. look down B. come across C. run after D. go by
Câu 16: A. around B. on C. in D. next