A .协方差
B . 方差
C . 相关系数
D . 标准差
A:安全提示标志
B:安全指示标志
C:安全警示标志
D:安全宣传标志
Don't ____ his tricks.
A. fall in
B. fall into
C. fall for
D. fall out
The police caught a young couple trying to ___ a huge quantity of heroin from somewhere in the Mediterranean.
A. export
B. relate
C. import
D. feed