quiet adj.安靜的
quite adv.非常，很
quit v. 放棄

dairy 牛奶的，奶制的
diary 日記

angle：角度，觀點(diǎn)
angel：天使

aboard 上飛機(jī)，上船
abroad 在國(guó)外
He was already aboard the plane. 他已經(jīng)登上飛機(jī)了。
She worked abroad for a year. 她在國(guó)外工作了一年。

principal/principle
principal：n. 校長(zhǎng) adj. 主要的，最重要的
principle: n. 原則，準(zhǔn)則，原理，定律
He's got no principles at all. 他一點(diǎn)原則都沒(méi)有！
The principal has no principles. 這個(gè)校長(zhǎng)沒(méi)有原則！

stuff
used when you are talking about things such as substances, materials, or groups of objects when you do not know what they are called, or it is not important to say exactly what they are
可以形容單個(gè)物體，What's this stuff？
可以作為一個(gè)統(tǒng)稱，比如，看看你桌上這些東西，Look at all the these stuff on your desk! 不講stuffs。

staff
all the workers employed in an organization 全體員工全體職員，單形復(fù)義
The staff were very good. 職員們都很棒。

economic：economy的形容詞，和經(jīng)濟(jì)，和財(cái)政有關(guān)的
economical：經(jīng)濟(jì)實(shí)惠的，節(jié)約型的
social, economic and political issues 社會(huì)的，經(jīng)濟(jì)的，政治的問(wèn)題
an economical car 經(jīng)濟(jì)型汽車，節(jié)油型汽車
It's more economical to use gas than coal. 用天然氣比燒煤更便宜。