一、 a bit 和 a little 在肯定句中修饰动词、形容词、副词和比较级时可以互换，表示"一点儿"的意思。例如:
修饰动词：
The speaker spoke up a bit/a little so as to make himself heard more clearly.
演讲者把嗓门提高了一点儿，以便使别人听得更清楚。
The sick child moaned a bit/a little, and then fell asleep.
那个生病的孩子呻吟了一会儿就睡着了。
修饰形容词：
He's a bit/a little mischievous.
他有一点淘气。
I'm afraid I'm a bit/a little muddled. I'm not exactly sure where to begin.
恐怕我有点糊涂了，我不确定该从何处着手。
修饰副词：
Please move a little further; you're standing in my light.
请移开一些，你挡我的亮了。
Can you speak a little slowly, Mr Bao?
鲍老师，你可不可以说慢一点吗？
修饰比较级：
Can't you walk a little faster?
你不能走快点吗？
On the weekend my husband and I get off work a little early.
周末，我和先生下班都比较早。
二、a bit 和 a little 在否定句中的意思恰恰相反，not a bit 相当于 not at all（一点儿都不）；not a little 相当于very(much)或extremely（很、非常）。例如:
not a bit:
She is not a bit tired. = She is not tired at all.
她一点都不累。
I'm really not a bit surprised.
我真的一点儿也不觉得惊讶。
He was not a bit like his father.
他一点儿也不像他的父亲。
not a little:
He was not a little annoyed.
他非常烦恼。
She was not a little worried about the expense.
她对那笔开支相当苦恼。
三、a little 可以直接作定语修饰不可数名词，而 a bit 则要在后面加 of 构成短语才能作定语 ，后面可以接不可数名词，也可以接可数名词。但是可数名词通常用单数，而且其前面应该有不定冠词。例如:
a little:
There is a little/a bit of food left for lunch.
午饭只能吃剩下的一点食品了。
A little/a bit water is enough for me.
我要一点点水就够了。
a bit of:
We got a bit of a scare.
我们受了点惊吓。
I do a bit of shopping for the missus.
我帮老婆买了一点东西。
四、a bit of 的另一种形式是 bits of, a little 则没有这种变体。例如:
Besides this, he used part of an old army wireless set, and some bits of wood.
除此之外,他还利用了一部分旧的军用无线电发报机的一部分零件和一些木片。
His ability to absorb bits of disconnected information was astonishing.
他吸收利用互不相关的零碎信息的能耐惊人。
She noticed some bits of fluff on the sleeve of her sweater.
她发现羊毛衫的袖口上起了一些毛球。
当 a little 修饰的名词前有 the, this, that, 所有格等限定词时，也要用 a little of 的结构：
See how my eyes brightened when I tasted a little of this honey.
你看，我尝了这一点蜜，眼睛就明亮了。
This remind me a little of those old sayings.
这使我想起了那些古老的谚语。
Add a little of the warmed milk and allow to froth a little.
加一点温牛奶，并让它起点儿沫。
五、a bit 通常修饰表示“令人不快”的形容词，例如sad, silly, cold, hungry, angry, difficult, heavy, expensive等; a little则无论褒贬都可以修饰，例如：
The song is a bit sad.
这首歌有点伤感。
You might say I’m a bit silly.
你可能会说我有点傻。
Mary is a little older but a little more beautiful than Ann.
玛丽比安年纪更大但是更漂亮。
Everyone seemed a little nervous.
每个人看起来都有点紧张。
六、a bit 和 a little 不能用来修饰“形容词 + 名词”的结构。例如：heavy boxes这样的结构，就不能用a bit和a little修饰，不能说a bit heavy boxes；再比如 hot weather，我们不可 以说a little hot weather.
七、a little bit 的意思是“一点点”，用法与 a bit 相同：
This is a little bit too difficult for me.
这对我来说有点难。
Jack is a little bit selfish.
杰克有点自私。
I speak a little bit of French.
我讲一点法语。
This made me feel a little bit better about myself.
这使我感觉好点了。
八、for a bit 和 for a little意思相同，相当于 for a while 或 for a short time，可互换。
We talked for a bit. = We talked for a short time.
我们谈了一会儿。
Please hang on for a bit.
请等一会儿，不要挂断。