1、We cannot legally conclude a peace treaty with Japan.

依照法律，我們無法同日本締結和平條約。

nobody could legally drink on the premises.依照法律，沒人可以在該場所飲酒。

~ sth (with sb) arrange and settle (a treaty, etc) formally and finally達成;決定;締結（條約等）:Britain concluded a trade agreement with China.英國和中國簽署了貿易協定.

2、They are nothing if not ambitious.

他們極為野心勃勃。

nothing if not：extremely; very極;非常;很:

The holiday was nothing if not varied.假日活動極其豐富多彩.

3、He is nothing if not a trouble-shooter.

他是個不折不扣的調解糾紛的專家。

4、Darkness released them from the last restraint.

他們趁著暗色擺脫了最后的束縛。

5、He really knew a thing or two.

（抱歉老師因為缺少語境，不太清楚這里想表達的意思，基本就是“略知一二”或“了解內幕”）

他還真地了解不少事情。

a thing or two1.真相；秘聞；內幕消息2.許多

knows a thing or two:十分精通；略知一二

6、We can not ignore our neighbors, only at our peril, can we ignore their distress.

我們不能對我們的鄰國置之不理，如果我們不顧及他們的安危，就只能自身難保。

The lesson we learnt was that the state can interfere with the private lives of people only at its peril.我們學到的教訓是國家在處于險境時能夠干預人民的私生活。

實際上想說的是“我們學到的教訓是國家要是干預人民的私生活就只會將自己置于險境。”

7、It is already four years since he was secretary general of the U.N.

他不擔任聯合國秘書長已經四年了。

若since引導的狀語從句的謂語動詞是終止性的過去時，則從句表示的時間是“從動作開始的那一時刻起”。如：

We have been missing them since they left here自從他們離開這里，我們就一直很想念他們。

若since引導的狀語從句的謂語動詞是持續性動詞或表示狀態的動詞的過去時時，則從句表示的時間是“從那持續動作或狀態結束時算起”。如：

John is now with his parents in New York, it is already three years since he was a teacher約翰現在和父母一起住在紐約，他不當教師已經三年了。

How long is it since you lived in Shanghai?你離開（沒住在）上海多久了？

8、It is already many years since the Second World War.

二戰結束后已經過去很多年了。

9、What he says can be taken as coming from horse’s mouth.

可以認為他說的話是可靠的。

straight from the horse's mouth:來自權威和可靠的消息；根據最可靠的消息來源；可靠地

What he says can be taken as coming from horse's mouth.可以認為他說的話是可靠的。

10、The British Prime Minister said, “They could throw every thing but the kitchen sink.”

英國首相說：“我們可以拋卻任何事情。”

分析：https://idioms.thefreedictionary.com/everything+but+the+kitchen+sink

everything but the kitchen sink：Nearly everything one can reasonably imagine; many different things, often to the point of excess or redundancy.

指lots of different objects.

11、 The British Prime Minister said,“the policies of western countries are like ducks in a row.”

英國首相說：“西方國家政策是一致的”。

ducks in a row一致(像鴨子似的一個接著一個)