After a few courses on painting，Helen said she would ________oil pointing in her spare time.

Many questions ________ at the meeting, but he answered none.

Their coming without notice really                    our difficulties.

We rushed to the football court, only to see a sign _____ into the ground reading PERIODIC MAINTENANCE (定期维修).

— What great changes have taken place in our city in the last few years!— Indeed, many high buildings have _______all over the city.