Question

He is study in a college(he is working in a

A factory)It _____A half year since he _______A college student A Is was B has been became C is became D has been became注,括号里表示一共两个题,除括号中部分不同外,后面部分及选项均相同,求大手帮忙解析并做比较

Answer 1

Working in the factory: A
It is a half year since he was a college student.
在factory工作了就是说明现在已经不是大学生了， 所以是大学生呢是过去的事情了。这个时候就不能用完成时了。因为老师总是说完成时要和现在有关系的（这个就是知识点），所以我们要排除B和D，B是完全没有这个形式的所以不用想它。
C的话后面是became就不对了，应该用was，表明过去是大学生，而现在不是了。（这个不是完全肯定但是应该会更好一点，因为became，成为在这里用意怪怪的）

Study in a college:D
这个就是和现在还有关系了所以要用完成时。
翻译一下：It has been a half year since he became a college student.
It has been a half year,已经半年了，什么半年了呢？since he became a college student,从他成为大学学生起。总体就是说，他已经成为大学学生半年了。

好吧这考的语法真的太刁钻了，正常来说除了在中国估计在别的地方都不会用到的。而且就算真的把这个语法点搞懂我相信自己写作文造句的时候还是不会用的。
加油吧。