Henry has come in his raincoat and gumboots ,_____for rain.
A:prepared
B:preparing
C:having prepared
D:prepares
如图,点A在半径为3的⊙O内,OA=3,P为⊙O上一点,当∠OPA取最大值时,PA的长等于( )
给下面加线的字注音
吞天沃日____ 如履平地____ 一舸无迹____
鲸波万仞____ 珠翠罗绮____ 艨艟数百____
用公式法解3x2﹣7x+1=0的正确结果是( )
若函数f(x)=(a﹣1)x在(﹣∞,+∞)上单调递增,则实数a的取值范围是____.