The police let him alone __________ the condition that he was staying in sight.
A. under
B. with
C. for
D. to
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The team won the gold medal __________ hard working and good cooperation.
A. by means of
B. according to
C. in regard to
D. in case of
It was a bad year for films, ____both quantity and quality.
A. regardless of
B. in spite of
C. in terms of
D. apart from
函数y=f(x)的凹凸性与y的二阶导数的联系,你认为正确的是
A. 连续函数y=f(x)在区间(a,b)是凹的,说明y的二阶导数大于0
B. 连续函数y=f(x)在区间(a,b)是凸的,说明y的二阶导数大于0
C. 连续函数y=f(x)在区间(a,b)是凹的,说明y的二阶导数不小于0
D. 连续函数y=f(x)在区间(a,b)是凸的,说明y的二阶导数大于1
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