17.【2020•长沙市】We are glad ________ that traditional Chinese medicine can work wonders in preventing some diseases.
A. know B. to know C. knowing
【答案】B
【解析】句意：我们很高兴地知道，中医在预防某些疾病方面可以发挥奇效。考查非谓语动词。know知道。know动词原形；to know动词不定式；knowing动名词或动词的现在分词。结合选项可知句子是说“很高兴知道……”，作表语的形容词glad后接动词不定式作原因状语。故选B。