A:一、四
B:二、四
C:三、四
D:一、三
— I'd love to, but I think we shouldn't __________ our progress. We also have a long way to go.
已知向量a→=(x2﹣3,1),b→=(x,﹣y)(其中实数x和y不同时为零),当|x|<2时,有a→⊥b→,当|x|≥2时,a→∥b→.
(I)求函数式y=f(x);
(II)若对∀x∈(﹣∞,﹣2}∪2,+∞),都有mx2+x﹣3m≥0,求实数m的取值范围.
我国南极科学考察队在南极进行科学考察时需要克服的恶劣气候是( )