问题
选择题
PSAs are often run _____ free, and are ______ to educate people about health, safety, or any other problem that affects public welfare.
A．for, mean
B．for, meant
C．of, to mean
D．in, meaning
答案
答案：B
固定词组。For free免费；be meant to do sth 想要做某事；句意：PAS构成是免费的。想要教育人们关于健康，安全，或者其它一些影响公共福利的问题。