【题目】Meyer and his team were the first ______ how the disease spreads from animals to humans.
A.showing
B.show
C.to show
D.shown

【答案】C
【解析】本题考查非谓语动词，非谓语动词作定语前有the only, thelast, the next,the first, the best 等序数词或形容词最高级时，必须用不定式。