— What will the weather be like tomorrow?
— It ________ be rainy, cloudy or sunny. Who knows?
A:must
B:might
C:shall
D:should
德国1871年宪法赋予皇帝的权力与法国1875年宪法赋予总统的权力区别很大。下列对其原因分析比较合理的是 ( )
若直线l1:ax+(3﹣a)y+1=0,l2:2x﹣y=0,若l1⊥l2,则实数a的值为____
We wear sunglasses to protect our eyes _____________ the sun.