老师您好，请问：

________（educate）in a key university is what many students long for.

这里应该填写它的什么形式呢？

解答如下:

以上句子有1个连词2个谓语动词,即主句谓语动词is,和表语从句的谓语动词long for.前面部分为主语内容,给出的是1个行为动词,因此需要填"该动词非谓语动词形式"充当.

educate 为行为动词,以下几种变化

(1)education 教育(为一抽象概念),如果填这个词,需要在前面加1个动名词,或者不定式即receiving education/to receive education 为更好些

Receiving education in a key university is what many students long for.

To receive education in a key university is what many students long for.

Education in a key university is what many students long for(欠妥，但不算错）

(2)educating  填这个词,当作及物动词,使用为"动名词表示抽象概念

Educating in a key university is what many students long for.

=What many students long for is educating in a key university.

(2)to be educated  填不定式被动语态,表示将要去一所重点大学接受教育,属于具体的一次性即将要发生的动作行为。即马上要去实现这个动作的情景。

To be educated in a key university is what many students long for.

=What many students long for is (逻辑主语for them) to be educated in a key university.

(3)being educated 填动名词被动语态,表示抽象被动概念.即属于泛指，还没有发生，只是一种抽象概念动作。这个动作行为还没有发生/也没有实现。只是一种想象情景而已。

Being educated in a key university is what many students long for.

=What many students long for is (逻辑主语for them/their) being educated in a key university.

备注：第1属于名词用，第2属于不及物动词用法，第3/第4属于及物动词用法

总结以上观点,基本都可以填,只是侧重意思不同而已，看你是哪种语境，根据不同语境选择最佳形式去表达即可.

我觉得，该句直接使用 Educating 似乎也不错，让动名词变成一种抽象的意义，不再突出主动被动概念。因为名词的education 在不同的搭配中，也具有主动和被动的含义。

Many young students long for educating in a key university.

我举几个例子，供参考：

1. his education of the children

他对孩子的教育 

2. after his education

在他受教育之后

3. He reckoned he should make a better fist at farming than educating. 

他认为自己搞农业会比教育更成功。

来自《简明英汉词典》

4. Another purpose of educating is to train students to be productive workers. 

教育的另一目标是培训学生成为高效率工作者。

问题中的句子，使用Education 肯定没错，但要求填写非谓语动词，所以，Educating 比 Educaion 更强调“行为”。