1.We must thank him .__C____good news he gave us![感叹句结构：1.What + 名词短语+主语+谓语!2.How + adj./adv.+主语+谓语!因为good news 是名词短语,排除B.又因为news是不可数名词,故排除A,选C]
A.What a B.How a C.What
2.__A____ useful information I've found on the Internet![感叹句,且information不可数]
A.What B.What an C.How
3.___B____heavily it's snowing!-[感叹句,且heavily是副词,故用how]
A.What B.How C.How a