Unit21课文中出现这样两个句子：（1）He made such rapid progress that before long he began to write articles in English for an American newspaper.(2)In fact,his English in one of these articles was so good that engels wrote him a letter and praised him for it.以上两句中出现了such…that和so…that句型，关于这两个句型在掌握时，我们应该注意些什么呢？
