Because of the high blood pressure, the doctor advised him to ______ from smoking.
A. constrain
B. restrain
C. refrain
D. remain
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He felt like a small boat on a(n) ___________ ocean.
A. enormous
B. huge
C. gigantic
D. vast
Who would be pardoned according to the news
A. Those having no connection with recent bombings.
B. Those who give up their weapons voluntarily.
C. Those who cooperate with the government.
D. Those who killed the American hostage.
u=f（x，y），x=rcosθ，y=sinθ，f具有一阶、二阶连续的偏导数，则urθ（）。
A. -fx·sinθ+fy·cosθ
B. rsinθcosθ(fyy-fxx)-fx·sinθ+fy·cosθ
C. rcos2θ·fxy-fx·sinθ+fy·cosθ
D. rsinθcosθ(fyy-fxx)+rcos2θ·fxy-fx·sinθ+fy·cosθ
What did the protestors demand
A. Resignation of the president.
B. Improvement in economy.
Changes in banking rules.
D. Increase in employment.
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