I thought we'd be late for the concert,           we ended up getting there ahead of time.

but

or

so

for

考查连词。句意：我以为我们音乐会迟到了，但是我们提前到达了那里。but 但是；or 或者；so 因此；for因为；两个分句在意义上bu是转折关系，故用but。故选A项。

I would really appreciate       if you can make time in your schedules to attend my lecture today.

that

it

this

one

考查形式宾语。句意：如果你今天能从日程安排中抽出时间来听我的讲座的话，我将不胜感激。I would appreciate it if/when...如果/当...时，我将非常感激。it 做形式宾语。故选B项。

So difficult __________ it to work out the problem that I decided to ask Tom for advice.

 I did find 

did I find

 I have found  

have I found

句子使用的基本句式为so…that…结构。按英语语法，当该结构的so…置于句首时，其后的句子(主句)要用倒装语序，如：So loudly did he speak that even people in the next room could hear him. 他讲话声音那么大，隔壁屋里的人都听得见。

The question of           English will keeping on changing in the future is easy         .

if; to answer

whether; to be answered

if; to be answered

whether; to answer

考查宾语从句和非谓语动词。句意：英语将来是否会继续变化这个问题很容易回答。第一空为宾语从句，从句中不缺少成分，表示“是否”，应用whether，if 引导的宾语从句不能充当介词的宾语，故排除A和C；第二空，这是be +性质形容词+不定式结构，这种结构中形容词说明不定式的特性，句子的主语是不定式的逻辑宾语。故选D项。