问题
选择题
Chinese President Hu Jintao called for an immediate cease-fire in Libya ______ an even worse humanitarian crisis in the country at the BRICS Summit in Hainan province.
A．to prevent
B．to have prevented
C．preventing
D．having prevented
答案
答案：A
考查非谓语动词。呼吁停火是为了阻止更大的人为灾难。不定式表目的和将来。所以用to prevent。而to have prevented表明阻止发生在呼吁之前，所以不正确。