问题 have there been serious attempts to是什么时态？怎么理解？

Only in the past few years have there been serious attempts to test these ideas.

问题 how far is it from A to B?

这里的from A to B 是在句子中做什么 ？和it的关系是什么？与How far is B from A有什么区别呢？

问题 require doing与require to do的用法区别

下面的句子摘自2018年高考英语天津卷阅读D:It takes practice and requires breaking some bad habits.请问这里为什么用 requires breaking? 难道不应该是 require to break 吗? 如果两者都对，它们有什么区别？

问题 不定式做定语的被动与主动问题（出现动作执行者）

语法书上说（不包括形容词+to do的各种类型）：一般来讲，在句中若出现了不定式动作的执行者时，则不定式用主动形式；若没有执行者，或不定式所修饰的成分是不定式动作的承受者，则不定式用被动形式。1）I have three letters...

问题 关于seem to be, seem like, 

seem 后面可以接 to be，但是可以接 like, as 吗？如： Mary seems to be a clever girl. Mary seems a clever girl. Mary seems as a clever girl. Mary seems like a clever girl. 以上四句都对吗？

问题 be at a loss what to do 的句子成分划分（可能涉及同位语）

I was at a loss what to do.请问这个句子如何划分句子成分? 有人认为 what to do 是同位语，但有人认为是错的。

问题 More than three million doses were to be made available 求语法分析

available是什么成份，网上把were to be made当做谓语，我觉得不对，were是系动词，to be made是非谓语动词做主语补足语，那available是什么成份呢？形容词后置修饰does？

问题 They have to move it 180 degrees 的句子成分

They have to move it 180 degrees.move 是谓语动词，it是间接宾语，180 degrees 是直接宾语是吗?

问题 make it up to sb（弥补）it指代什么

I will make it up to you after I finish my work in a few days!句中it指代什么，in a few days修饰finish还是make？

问题 to get away from an inferno修饰的是什么

...al Canadian Mounted Police snaked through the outskirts of the remote city to get away from an inferno that has now charred 390 square miles of territory and devoured more than 1,600 structures.请问：to get away from an inferno 修饰的是什么？

问题 带不定式作宾语补足语的动词（遇到情态动词、使役动词、感官动词）才省略to吗

Britain and France decided to help Turkey fight Russia.老师，fight是动词，这个也是带不定式作宾语补足语，才省略了to。help,如果后面不是补足语就不能省略了吗？

问题 He made a mental note to ask Alan about it(不定式的成分）

He made a mental note to ask Alan about it.to ask Alan about it作什么成分?

问题 是get to think还是get thinking

问题 begin to do和begin doing区别

问题 be said to do 是什么语法点