Question

Have you realized the difficulty we have ____ the problem?

A．worked out

B．to work out

C．work out

D．working out

Answer 1

D

考查固定句型。have difficulty/trouble (in) doing sth.“做某事有困难”。句意“你意识到我们在解决这个问题时，遇到的困难吗？”根据固定句型可知，选D。