[判断题]半导体三极管能够放大的外部条件是发射结正偏，集电结反偏。
A.正确
B.错误

Recent years have brought minority-owned businesses in the United States unprecedented opportunities—as well as new and significant risks. Civil rights activists have long argued that one of the principal reasons why Blacks, Hispanics, and other minority groups have difficulty establishing themselves in business is that they lack access to the sizable orders and subcontracts that are generated by large companies. Now Congress, in apparent agreement, has required by law that businesses awarded federal contracts of more than ＄ 500,000 do their best to find minority subcontractors and record their efforts to do so on forms filed with the government. Indeed, some federal and local agencies have gone so far as to set specific percentage goals for apportioning parts of public works eon- tracts to minority enterprises.
Corporate response appears to have been substantial. According to figures collected in 1977, the total of corporate contracts with minority businesses rose
A. disadvantage in the sizable orders and subcontracts that are generated by large companies.
B. been denied bank loans at rates comparable to those afforded larger competitors.
C. not had sufficient opportunity to secure business created by large corporations.
D. not had adequate representation in the centers of government power.