We built this factory ______ top speed andminimum(最少的) cost.

Raising ________ retirement age in progressive steps is in ________ line with China’s labor market realities and should be prioritized, an official said Tuesday.

The fact __________she hasn’t know the result of the examination is a great surprise to me.

Mr. Wu found a number of magazines in theclassroom ______________.

The parents can’t explain _______ makes their children so fascinated with their teacher’s lessons.