问题补充:
A new study has found no evidence that the sunscreen, commonly used to reduce the risk of skin cancer, actually the risk.
A. increase
B. increasing
C. increases
D. having increased
答案:
A. increase
B. increasing
(答案→)C. increases
D. having increased
解析:考查句型结构。根据句子结构可知该词作句子的谓语。句子完整机构为是the sunscreen actually increases the risk。 commonly used to reduce the risk of skin cancer作the sunscreen的定语。