C 是正确答案,so that 后面加的是完整的一个句子;
如果选择B ,则后面加的是He works hard at English in order to be an English teacher in future;
没有A such that 这个搭配.in order to 为了
所以原句的意思是为了将来成为一个英语老师他现在努力学习英语.
D so as to 是“以便于”的意思,后面也加动词,而不是句子.
例如:He came with the dictionary so as to refer to it when needed.他带来了字典便于需要时查阅.