他打开笼子，把鸟儿放生了。

He opened the cage and ___set the birds ___free.

战争结束后，许多战俘被释放了。

After the war, many prisoners of war were ___set ___free.

活动家们努力为那位被冤枉的人争取自由。

The activists fought to ___set the wrongly accused man ___free.