如果抛物线方程y2=-16x,那么它的焦点到准线的距离等于() (A)2 (B)4 (C)8 (D)16
A.eventB.activitiesC.sportD.play
A. event
B. activities
C. sport
D. play
If law and order__________not preserved,people will notBe able to live a secure life.
A. are
B. were
C. is
D. was
A.anywhere B.here C.carefulD.compare
A. anywhere
B. here
C. careful
D. compare