Although（ ）primarily to promote

Although（ ）primarily to promote trade relations, these agreements also foster technological cooperation.
A、designed
B、they are to be designed
C、it is designed
D、they are being designed
【正确答案】：A
【题目解析】：句意：这些协议虽然主要是为了促进贸易关系，但其实也促进了技术合作。although在让步等状语从句中，如果从句主语和主句主语相同，或者从句主语是it时，从句的主语和谓语动词的一部分经常省略。