几个英语问题1,Covering an area of 57square kilometers and holding

几个英语问题
1,Covering an area of 57square kilometers and holding 600 million cubic meters of water ,hongfeng lake is the largest lake in guizhou
这里的cover是不是占地意思 我一开始以为是被什么覆盖着 选的covered
2,Now that we have not got a suitable candidate ,we might as well give him a chance
为什么不可用 would or should
3,It was not until i stayed on the bus for twenty minutes that i realized i had taken the wrong bus 为什么是not until 不可以是until吗 不用倒装吗

从后往前回答吧：
【3】it was not until ,it was until 都用于强调句结构,表示强调.It was not until 意思是：直到.才.表示在这个界限之前一直没有发生这个动作；it was until 意思是：直到.表示这个动作一直延续到这个界限出现时.如
1 He didn't come until 8:00---------------It was not until 8:00 that he came(他直到八点才来)
2 He waited until / till 8:00 un the evening.----------It was till / until 8:00 that he waited（他一直等到八点）.
例句中上车二十分钟了才知道上错车了,表示他一直没意识到上错车,直到20分钟的时候才意识到.这是一个固定的强调句式.至于你说的倒装,倒装句是not until位于居首时,句子要倒装例如,Not until she came back did I know she was OK.
强调句是对not until 强调,例如 It was not until 11 o'clock that he returned to his home.
【2】might] (just) as well…是一个固定搭配,意为“不妨”、“还是…为好”等,用 might 比用 may 语气更委婉.如：
I’m ready,so I might as well go now．我已准备好,因此不妨现在就走.
There’s nothing to do,so I may [might] as well go to bed.既然没什么事可做,我还是去睡觉为好.
例句中既然我们没有一个合适的人选,我们不妨给他一个机会,表示的是一种征询的语气,语气比should和would更委婉.并且now that 和might as well 是一种常见的近乎于固定搭配的语言习惯.
【1】A.分词作定语现在分词表“主动又正在进行着”过去分词表“被动且已经完成了”.如The crying girl is my daughter.
The apartment （that was）bought last year is now worth more money
B.分词作状语（关键找逻辑主语）
a)放在句首的分词往往看作时间状语以及原因状语.如 Looking (when I looked) at the picture,I couldn't help missing my middle school days.
Seriously injured,Allen was rushed to the hospital.=As he was seriously injured,Allen was rushed to the hospital.
b)放在句中或句末常常看作为伴随状态(并列句)The girl was left alone in the room,weeping（crying ）bitterly.
例句中就是用的covering做伴随状语的,于此类似还有
Containing 39 percent alcohol,the liquor accounts for half of the factory's 100 tons of exports each year.
此酒含39%的酒精,占工厂每年出口100吨酒的一半.
Originating in South China,Kunqu reached its peak in the Ming Dynasty(1368-1644)．
昆曲起源于华南,在明朝(1368-1644)达到顶盛时期.