$12.$ A $-$ third largest
(Dẫn chứng ở câu 2: It is the third largest in the whole world)
$13.$ D $-$ continents
(Dẫn chứng ở câu 4 dòng 3: The United States has tall mountains, wide plains, deserts, hills, rivers, lakes, volcanoes and even rainforests)
$14.$ D $-$ 3
(Dẫn chứng ở câu 4 dòng 2: Prts of the United States touch three different oceans)
$15.$ A $-$ North America
(Dẫn chứng ở câu 3 dòng 1: It is located in a continent called North America)
$16.$ D $-$ the largest state/ a chain of islands
(Dẫn chứng ở câu cuối: Alaska is the largest state and Hawaii is a chain of islands in the Pacific Ocean.)
$17.$ C $-$ had
$18.$ A $-$ turn off
$19.$ D $-$ will be having
$20.$ D $-$ Sending letters
$21.$ B $-$ came
$22.$ B $-$ due to
