物体在恒定的合力作用下做直线运动，在时间t₁内动能由零增大到E₁，在时间t₂内动能由E₁增加到2E₁，设合力在时间t₁内做的功为W₁，冲量为I₁，在时间t₂内做的功是W₂，冲量为I₂，则 [ ]

A．I₁＜I₂，W₁=W₂ 　

B．I₁>I₂，W₁=W₂

C．I₁> I₂，W₁＜W₂ 　　

D．I₁=I₂，W₁＜W₂

Today's weather isn't as it was yesterday, _____? [ ]

A. wasn't it

B. is it

C. was it

D. isn't it