And the next few days could prove difficult for the president.

Music proved too difficult for him, however, and he wanted to act from an early age.

Can someone help me with these questions that have proven difficult to answer on my own.

But finding him may prove more difficult than I expected.

As for the other two, that may prove more difficult.

It is those in the large middle group that prove difficult.

But few ideas have proved so difficult to put into effect.

As it was the next two years proved very difficult.

However it proved a little more difficult than he thought.

The idea is simple and effective, but proved more difficult to use than might have been expected.