若整式4x2+Q+1是完全平方式,请你写一个满足条件的单项式Q是( )
±4x、4x4、﹣4x2、﹣1中任意一个
She made the demand that the journalists _____ at once ______ Iraq.
A.leave; for
B.leave; to
C.left; to
D.to be left; for
如图所示,长2m,质量为1kg的木板静止在光滑水平面上,一木块质量也为1kg(可视为质点),与木板之间的动摩擦因数为0.2.要使木块在木板上从左端滑向右端而不至滑落,则木块初速度的最大值为( )
A.1m/s
B.2m/s
C.3m/s
D.4m/s