troposphere

n [sing] (usu 通常作 the troposphere) layer of the atmosphere that extends about seven miles upwards from the earth's surface 对流层（距地表约七英里）.

trod, trodden, troglodyte, troika, Trojan, Trojan horse, troll, trolley, trolley bus, trollop, trombone, trombonist, troop, troop-ship, trooper, trope, trophy, tropic, tropical, tropically, Trot, troth, Trotskyism, Trotskyist, trotter, troubadour, trouble, trouble-maker, trouble-shooter, trouble-spot, troubled, troublesome, trough, trounce, troupe, trouper, trouser, trouser-suit, trousers, trousseau,