计算机操作系统中，若WAlT、SIGNAL操作的信号量S初值为3，当前值为-2，则表示当前有()个等待信号量S的进程。
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The passage suggests that____.
A. buying and selling securities is dishonest
B. investing in securities is unwise
C. some exchanges provide market services for several kinds of products
D. the government has been playing an important role in controlling dishonest practices on the exchanges
Investing in securities has been safer by the____.
A. Chicago Mercantile Exchange
B. Chicago Board of Trade
C. Securities Exchange Commission
D. Commodity Exchange
What is the main idea of the passage？
A. With determination and persistence, Juliette started Girl Scout troops all over the world.
B. Juliette, a lucky deaf woman, always got whatever she wanted.
C. Juliette, traveled to many different places in her life time but ended up back in Savannah.
D. Without Juliette, the Girl Scouts would still be a British phenomenon.
A sudden, sharp decline in the value of securities is called_____.
A. a trade
B. speculation
C. investment
D. a crash
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