单项选择题 Mother wanted to be a good provider, a role she _____ since her marriage to Father.A.shouldersB.shoulderedC.is shouldering D.has been shouldering

单项选择题 We give time upace and love we can spare, and _______ , dogs gine us tea all.A.in all B.in factC.in short D.in return

单项选择题 预应力筋由多根钢丝或钢绞线组成时，同束内应采用（）的预应力钢材。