境内机构从事对外贸易活动收取的外币现钞办理结汇应向银行提供哪些材料（）.

A、对外合同

B、发票

C、盖有海关验讫章的出口收汇核销单

D、海关签章的入境申报单正本

Changing rescuers while carrying out artificial respiration should be done（）.

A.without losing the rhythm of respiration

B.only with the help of two other people

C.by not stopping the respiration for more than 5 minutes

D.at ten minute intervals