concentration n.專(zhuān)心；集中（注意力）
This thesis will need all your concentration. 這篇論文需要全神貫注才能讀懂。
含量（百分比）
What is the concentration of salt in sea water? 海水中鹽的含量是多少？
Contamination n. 玷污, 污染, 污染物
Content adj. 滿(mǎn)足的；滿(mǎn)意的；甘愿的
She is content with very little. 她易于滿(mǎn)足。
We should never content ourselves with a little book knowledge only. 我們切不可滿(mǎn)足于僅僅有一點(diǎn)點(diǎn)書(shū)本知識(shí)。
（常與to連用）滿(mǎn)足于…的
The old couple seem content to sit in front of the television all night. 老夫婦倆似乎整夜坐在電視機(jī)前就心滿(mǎn)意足了。
Content vt. 使（人或自己）滿(mǎn)足；使?jié)M意；使安心
Nothing contents her, she is always complaining. 沒(méi)有什么能使她滿(mǎn)意，她總是抱怨。
Content n. 滿(mǎn)意；滿(mǎn)足；安心
to one's heart's content心滿(mǎn)意足
content 2 n.（書(shū)、報(bào)紙等的）內(nèi)容，目次，目錄
"It is advisable to look at the contents page of a book, before buying it." 買(mǎi)書(shū)前是先看一看目錄。
含量
the content of silver in a ton of ore一噸礦砂中銀的含量
(pl) 內(nèi)容；所容之物
The contents of the box fell onto the floor. 這個(gè)盒子里的東西掉到地上了。
conventional allowance 合同公差
conventional adj. 因襲的；傳統(tǒng)的，習(xí)慣的
conventional accounting 傳統(tǒng)會(huì)計(jì)（不使用計(jì)算機(jī)，依靠人工記帳的會(huì)計(jì)）
常規(guī)的；普通平凡的
conventional weapon常規(guī)武器
allowance n. 津貼；補(bǔ)助
travelling allowance 出差津貼
an allowance of $10000 a year每年補(bǔ)助1 萬(wàn)
corrosion n.侵蝕, 腐蝕狀態(tài)
counting of bacteria 細(xì)菌計(jì)數(shù)
crack n. 破裂聲；爆裂聲
a crack of thunder雷聲
裂縫；縫隙
There's a crack in this cup.這只杯子有一條裂縫。
The door opened just a crack.這門(mén)只打開(kāi)一條縫。
分裂；裂開(kāi);突然的重?fù)?試圖；嘗試
He said he didn't know how to swim but would take a crack at it.\他說(shuō)他不會(huì)游泳，但將盡力嘗試。
笑話(huà)；玩笑；閑談;（嗓子的）變音，粗啞
criterion n. (批評(píng)判斷的)標(biāo)準(zhǔn), 準(zhǔn)據(jù), 規(guī)范
cross twist 順手捻，S捻
This thesis will need all your concentration. 這篇論文需要全神貫注才能讀懂。
含量（百分比）
What is the concentration of salt in sea water? 海水中鹽的含量是多少？
Contamination n. 玷污, 污染, 污染物
Content adj. 滿(mǎn)足的；滿(mǎn)意的；甘愿的
She is content with very little. 她易于滿(mǎn)足。
We should never content ourselves with a little book knowledge only. 我們切不可滿(mǎn)足于僅僅有一點(diǎn)點(diǎn)書(shū)本知識(shí)。
（常與to連用）滿(mǎn)足于…的
The old couple seem content to sit in front of the television all night. 老夫婦倆似乎整夜坐在電視機(jī)前就心滿(mǎn)意足了。
Content vt. 使（人或自己）滿(mǎn)足；使?jié)M意；使安心
Nothing contents her, she is always complaining. 沒(méi)有什么能使她滿(mǎn)意，她總是抱怨。
Content n. 滿(mǎn)意；滿(mǎn)足；安心
to one's heart's content心滿(mǎn)意足
content 2 n.（書(shū)、報(bào)紙等的）內(nèi)容，目次，目錄
"It is advisable to look at the contents page of a book, before buying it." 買(mǎi)書(shū)前是先看一看目錄。
含量
the content of silver in a ton of ore一噸礦砂中銀的含量
(pl) 內(nèi)容；所容之物
The contents of the box fell onto the floor. 這個(gè)盒子里的東西掉到地上了。
conventional allowance 合同公差
conventional adj. 因襲的；傳統(tǒng)的，習(xí)慣的
conventional accounting 傳統(tǒng)會(huì)計(jì)（不使用計(jì)算機(jī)，依靠人工記帳的會(huì)計(jì)）
常規(guī)的；普通平凡的
conventional weapon常規(guī)武器
allowance n. 津貼；補(bǔ)助
travelling allowance 出差津貼
an allowance of $10000 a year每年補(bǔ)助1 萬(wàn)
corrosion n.侵蝕, 腐蝕狀態(tài)
counting of bacteria 細(xì)菌計(jì)數(shù)
crack n. 破裂聲；爆裂聲
a crack of thunder雷聲
裂縫；縫隙
There's a crack in this cup.這只杯子有一條裂縫。
The door opened just a crack.這門(mén)只打開(kāi)一條縫。
分裂；裂開(kāi);突然的重?fù)?試圖；嘗試
He said he didn't know how to swim but would take a crack at it.\他說(shuō)他不會(huì)游泳，但將盡力嘗試。
笑話(huà)；玩笑；閑談;（嗓子的）變音，粗啞
criterion n. (批評(píng)判斷的)標(biāo)準(zhǔn), 準(zhǔn)據(jù), 規(guī)范
cross twist 順手捻，S捻