这两个动词是burn的过去式和过去分词；
流行说法是在句子中的用法不同，通常有宾语时用“burnt”，没宾语时用“burned”，如：
a.
The love of freedom burned in our hearts. 对自由的热爱之火焰在我们心中燃烧。
The candle has burned brightly for the whole night. 蜡烛燃烧了整整一夜。
A lighted cigarette burned a hole in his clothes.
点着的香烟在他衣服上烧了一个洞。
《汉英大词典》
The oil in the lamp had burned up.
灯里油已经烧尽了。
《汉英大词典》
The candle had burned right down
这根蜡烛完全烧尽了。
《柯林斯高阶英汉双解学习词典》
A wood fire burned in the grate.
木柴在炉栅中燃烧着。
《柯林斯高阶英汉双解学习词典》
例外：Protesters set cars on fire and burned a building.
抗议者焚烧汽车，并烧毁了一座建筑。
The guerrillas burned down the enemy's depot.
游击队放火烧了敌人的仓库。
《汉英大词典》
Coal fell out of the fire, and burned the carpet.
炉火中迸出的煤块烧着了地毯。
《柯林斯高阶英汉双解学习词典》
He burned his hands at the glass-works.
他在玻璃厂烧灼了手。
《汉英大词典》
Demonstrators ransacked and burned the house where he was staying
示威者搜遍了他的住处，并放火烧了那里。
《柯林斯高阶英汉双解学习词典》
b.
Who has burnt the paper? 谁把文件烧了？
Jane burnt all the letters from her former boyfriend. 简把她以前男朋友的信都烧掉了。
I burnt the toast.
我把面包烤糊了。
The acid has burnt a hole in my jacket.
这种酸把我的上衣烧了一个窟窿。
《汉英大词典》
He covered his tracks, burnt letters and diaries
他掩盖形迹，烧毁了信件与日记。
《柯林斯高阶英汉双解学习词典》
The pancake is burnt.
饼烤焦了。
《汉英大词典》
Her mother had bundled all her Forties clothes up and burnt them.
她母亲把她四十几岁时穿的所有衣服都包起来烧掉了。
《柯林斯高阶英汉双解学习词典》
He looks very ill; he must have burnt the candle at both ends.
他看上去病得很厉害，一定是劳累过度了。
《汉英大词典》
To keep warm they burnt wood in a rusty oil barrel
他们在一只生锈的油桶里烧木柴来保暖。
《柯林斯高阶英汉双解学习词典》
综上所述，小编认为区别的界限不是很明显。
