The problem is so difficult that（) of us can work it out.

What can we learn about the childrens homework from the passage？A．It is so difficult for t

Its not so much that the machine is out of order______ （that) I have not learned to operat

Its an_____difficult problem, which even many professionals cannot work out.A．exceedinglyB

Its such a difficult problem______no one can work it out.A．asB．thatC．soD．this

The markings are so blurred that it is difficult

The markings are so blurred that it is difficult