His sister left home in 1998, and _______since.
He _______ English for four years before he went abroad.
Carelessness always contributes _______ car accidents. Therefore, drivers are advised to concentrate their attention _______ driving.
With a lot of difficulties _______, they went to the seashore and had a good rest.
The number of people present at the meeting _______ two hundred and a number of them _______ from the countryside.
Giving up smoking is a slow and painful _______ for him.