—I feel a little nervous ____ the exam . —______. All of the students may feel nervous.
A:take, Don't worry.
B:taking, Take it easy
C:to take, Don't be worried
D:took, Come on.
人口增长过快产生的危害是( )
解方程组:{x+y=22x+z=-27y+z=7.
已知双曲线x2a2-y2b2=1(a>0,b>0)的左、右焦点分别为F1,F2,以F1F2为直径的圆与双曲线在第一象限的交点为P.若∠PF1F2=30°,则该双曲线的离心率为____
写出一个你喜欢的比例.
α是锐角,且sinα>32,则α( )