PSAs are often run _____ free, and are ______ to educate people about health, safety, or any other problem that affects public welfare.
.______ was wrong.
.“______ twenty dollars a big sum to her?” “I suppose so.”
.Three hours ______ enough for us to finish the task.
.Most of his savings ______ in the Xin Hua Bank.
.All that can be done ______.