Question

12. ―Do you know Hetty very well? ―Yes ， she and  I_friends since we met in Guang?zhou last summer. A.have made B.have become C.have been I). have turned

Answer 1

12. C 由日寸间状语从句since  we met in Guangzhou last summer

可知空格处所填词所表示的状态从过去某时开始一直延续

到现在，而make,become和tum都是瞬间动词，不符合题意。