The use of money is not limited to high civilizations; actually many primitive peoples have______ moneys of their own.

单项选择题No other drug is available at present______ can produce the same therapeutic effect with less risk.

单项选择题Many foreign students come to study in the U.S., some ______ by scholarships, others by the U.S. government' s Agency for International Development, by the Ford Foundation, and so on.