Unit 1 Unsolved Mystery——THE SEA

Unit 2 Winter Comes to the Animal World

Unit 3 LOST OVER THE ATLANTIC

Unit 4 The Stars of the Magi

Unit 5 BURIED TREASURE

Unit 6 LADY of the Wasteland

Unit 7 EIGHTEENTH CENTURY STYLE

Unit 8 THE GIANTS OF EASTER ISLAND

Unit 9 Michigan's Marching Dunes

Unit 10 V-DAY IN THE POLIO WAR

Unit 11 Sputtering African Fuse

Unit 12 TWO FOR A NICKEL

Unit 13 The"UPSTART CROW"

Unit 14 THE REAL SHERLOCK HOLMES

Unit 15 Is Your Judgment Warped?

Unit 16 The Truth about Those"INVISIBLE"Ads

Unit 17 Edward R.Murrow Reports on Britain Under Bombs

Unit 18 IS a Race of Robots Possible?

Unit 19 The War Against Hunger

Unit 20 Come Aboard an Atomic Sub!

Unit 21 Superstitious?Here's Why!

Unit 22 The Cloak-and-Dagger Struggle to Keep New Cars Secret

Unit 23 Jerry Potts,Scout Supreme

Unit 24 Danger by Candlelight

Unit 25 STRANGE MONEY

Unit 26 THE GREAT CHICAGO FIRE

Unit 27 1066 AD——THE NORMAN CONQUEST

Unit 28 WHO KNOWS?

Unit 29 THE BEGINNING OF THE HEALING ART

Unit 30 WHAT'S SO FUNNY?

Answer Key（另附）