______ (T/t)hey were still working in the field ______ it rained heavil.
A：/; but
B：/; although
C：Although; /
D：Although; but
I was sad that she my invitation.
下列不属于调查的是（ ）
男女生之间不可能建立纯真的异性友谊，因此男女生尽量少交往。（ ）
