问题补充:
单选题Whenhelookedup,hesuddenlyfoundhimselfbyagroupofteenagers,A.to be surrounded;B.surrounded;C.be surrounded;D.having been surrounded;
答案:
B解析考查过去分词作宾补,此题考查的结构是find sth/sb done,句意:当他抬头的时候,他突然发现他自己被一群青少年包围着。be surrounded by被什么包围,在这里surrounded做宾补。所以选B。