_______ by keeping down costs will Power Data hold its advantage over other companies.

Only  

Just 

 Still  

Yet

考查倒装句式。句意：只有通过降低成本，Power Data才能比其它公司更有优势。A只有；B仅仅；C仍然；D然而。Only加副词、介词短语或时间状语，放句首时，用部分倒装。故选A。

used to

used to be

used to do

was used to

考查词组和省略式，used to do“过去常常’,be used to do “被用来做”，句意是：--你现在是志愿者吗？--不但我过去是，去年我为市运动会工作。可以排除D项，因为这是省略句，完整的是I used to be a volunteer。英语中如果不定式的部分是重复上文可以省略to后面的内容，但是如果to后面是be动词或助动词have，就不省略。选B。

---Shall I tell Jhon about it?

---No, you            . I've told him already.

needn't

wouldn't

mustn't

shouldn't

考查情态动词。句意：---要我告诉约翰这件事情吗？--不，不必了，我已经告诉他了。A.needn't不必；B. wouldn't不会；C. musn't禁止，不允许；D. shouldn't 不应该。根据“I've told him already”，可知这里是“不必要”。故选A项。

How I wish every family         a large house with a beautiful garden!

has

will have

had

had had

考查虚拟语气。句意：我多么希望每个家庭都有一个带着美丽花园的大房子！此句是wish 引导的从句，从句要用虚拟语气，根据wish 可知是与现在事实相反，从句一般用过去时。故选c项。

— Father, you promised!

—Well,____．But it was you who didn't keep your word first．

so was I 

so did I 

so I was 

so I did

考查部分倒装“So + be/情态动词/助动词 + 主语”与表强调的“So + 主语 + be/情态动词/助动词”区别。根据语境“you promised（你许诺过）”和答语“But it was …”可知爸爸回答“我的确许诺过”，且promised是过去时，所以表强调要用助动词did,故选D。句意：——爸爸，你许诺过。——好啦，我的确许诺过。但是是你先没有遵守诺言。