1.   His orgasms seemed to him to be perfectly genuine, but once Maisie had an idea in her head it proved difficult to shift.

2.   His precautions were justified, for when he reached Sweden it proved difficult even to find accommodation for his servants.

3.   Any decisions that prove too difficult to make in consensus with Russia can be pulled off the agenda at the request of any member nation, the officials said.

4.   Besieged as it is, the Clinton presidency may prove difficult to judge, says Allan Lichtman, a history professor at American University here.

5.   Breaking himself of the habit of stealing her dentures, however, may prove more difficult.

6.   But graduating from small-town honky-tonks to big-city clubs proved difficult.

7.   But overcoming the obstacles, from a broken-down power-generating system and vast corruption to the effects of a summer drought and Russian meddling, proved too difficult.

8.   But their integration proved more difficult.

9.   But the long-term may prove more difficult if California heads into a severe recession.

10.   But this mystery was proving more difficult.