The United States______a population of over 200 millions.A．have hadB．is havingC．haveD．has

______ is the longest river in the United States.A．The Waikato RiverB．The Mackenzie RiverC

In the United States, the Senate is presided over by______of the United States.A．the presi

In the United States, ______is called the "Father of Waters".A．the Mississippi RiverB．the

The United States consists of two noncontiguous states: Alaska and______.A．TexasB．HawaiiC．

The Industrial Revolution was first realized in______.A．FranceB．EnglandC．the United States

The national bird of the United States is______.A．sparrowB．swallowC．eagleD．swan