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

In a______market, its difficult to sell goods unless you lower your prices.A．depreciatedB．

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

Adopted children may present special problems, such as______.A．delayed motor skills develo

This problem is very difficult to deal with. It’s really_______.A、convincingB、seriousC、t

We want to know what is the best way to find______to this extremely difficult problem.A．an

Having considered the problem over and over again, he regretted having made such a______de