问题
People send out sky lanterns to ask for help when in trouble, but now sky lanterns celebrating the festivals.
A:used to; are used to
B:used to; are used for
C:are used to; are used for
D:are used to; are used in;
B:used to; are used for
C:are used to; are used for
D:are used to; are used in;
正确答案是: