The first thing I did was to see if there were any products might help me, but there only seemed to be powders to kill snakes.
A. that; /; designed
B. which; that; designed
C. /; that; designed
D. /; which; design
网友回答
A. that; /; designed
B. which; that; designed
(答案→)C. /; that; designed
D. /; which; design
解析：考查定语从句和分词用法。第一空省略that/which, that/which指代先行词the first thing作为did的宾语；第二空that指代any products在句中做主语，不能省略。Design与powders构成被动关系，所以使用过去分词。