—It's no easy task to catch a ticket on a website that receives 1 billion clicks daily.—I

—It's no easy task to catch a ticket on a website that receives 1 billion clicks daily.
—I can't agree with you more. There be errors for every single step.
A. should
B. must
C. can
D. will

A. should B. must(答案→)C. can D. will解析：选C　考查情态动词表示推测。句意：“在每天被点击十亿次的网站上抢到一张票不是容易的事。”“我非常同意你的说法。每一步都有可能出错。”can用于肯定句表示理论上的可能，即用来说明主语的特征。

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我好好复习下

A. might grow; hadn't wateredB. needn't have grown; didn't water(答案→)C. would have grown; didn't waterD. would grow; hadn't watered解析：考查虚拟语气和时态的用法。句意：去年春天种树的时候发生了什么事？这些书本可以长的很好，但是他们没有细心照料。would have done 是对过去事情的虚拟，本可以做却没做，第二空根据后面使用了转折but 来看。表示事实上没有浇水，是过去的事实，用一般过去式，选C。