________ their heavy load, the two brothers walked along the river bank.

.—What are you busy with?—The conference___________in our city next week, as you know.

The two old sisters, _______ so long, held each other and burst into tears. 

All the citizens strongly insist those found _____ "harmful" advertisements in the street should be punished strictly．

In the future, senior citizens will be able to go anywhere using high-tech cameras _______ to their head.