The children were allowed to do____they liked

注意：no matter 不能引导主语从句和宾语从句。

"no matter +疑问词" 或"疑问词+后缀ever" 。

例如：
No matter what happened, he would not mind. =Whatever happened, he would not mind.
不管发生什么，他不在意。

替换：
no matter what = whatever
no matter who = whoever
no matter when = whenever
no matter where = wherever
no matter which = whichever
no matter how = however

注意：no matter 不能引导主语从句和宾语从句。

(错）No matter what you say is of no use now.（对）Whatever you say is of no use now. 你现在说什么也没用了。（Whatever you say是主语从句）

（错）Prisoners have to eat no matter what they're given.
（对）Prisoners have to eat whatever they're given.囚犯们只能给什么吃什么。

whatever有N多个意思，no matter what只是其中一种。
1）Everything or anything that:
无论什么，任何东西，一切事物。这里取的就是这个意思。2）no matter what

你花时间纠结这个问题，不如多背几个单词