The ducks _______ swimming in the river.[ ]
A. am
B. is
C. are
答案：C
下列哪项不是影响骨折愈合的因素：（）。
A.骨折断面的接触
B.损伤的程度
C.伤口的处理
D.感染
E.断端的血供
—The exam was too difficult, wasn’t it?
—Yes, I don’t think ______ could pass it.
A．somebody
B．anybody
C．nobody
D．everybody
