She concentrated her energies __________ her test.
With a lot of difficult problems _______, the newly-elected president is having a hard time.
_______ late in the afternoon, Bob turned off the alarm.
The picture _______ on the wall is painted by my nephew.
_______ the general state of his health, it may take him a while to recover from the operation.
In order to gain a bigger share in the international market, many state-run companies are striving _______ their products more competitive.